Wikipedia talk:WikiProject Elements/Archive 52

The actual formal group 3 proposal
Should the periodic table on WP be presented in this form (Sc-Y-La):

or this form (Sc-Y-Lu)?

Note that this is not going to be about the categorisation. The only topic I plan to have discussed here is the group 3 issue.


 * A question, for clarification: these are navboxes, so on a tertiary presence level (they don't even show in mobile view). I assume the proposal is to apply this note to ~every PT at enwiki, especially the top ones. (Exceptions needed? I think we can even manage to add this to the micro  one :-) ). -DePiep (talk) 15:51, 18 October 2020 (UTC)
 * Yes. ^_^ Double sharp (talk) 16:17, 18 October 2020 (UTC)

Added later: the precise wording of the footnote is open to discussion, and the important thing is just that there be one. So even if you don't like the footnote in either option, you can first write which form you prefer to have in terms of the main PT, and afterwards discuss how to change the footnote. The important question is which form you support as the main one and relegating the other to the footnote. Double sharp (talk) 00:04, 19 October 2020 (UTC)
 * Idea: we could repeat (copy) the "3[NB]" group header in both places, whichever outcome. Visual aid, makes the footnote easier & shorter. -DePiep (talk) 16:45, 20 October 2020 (UTC)
 * Do you mean to have the 3 group header also atop La and Ac? I worry that this may confuse the situation being shown. In the first table above Sc-Y-La is shown and Sc-Y-Lu is correctly described in the footnote; in the second, they are the other way round. But if we duplicate "3" above La and Ac we end up showing as the primary thing what looks like the "bifurcated group 3" option which is quite rare and not one of the options IUPAC says it'll decide on.
 * This said, a possible idea I had in cases where there may not be space for a real footnote is to have a tooltip. So you'd mouseover the "3" and it'd give you the footnote even when there's no space for it. I am honestly not sure how it'd work for the micro PT because there not even the element symbols, much less the group numbers, are there. But we can decide on all that afterwards. Double sharp (talk) 23:21, 20 October 2020 (UTC)
 * Yes, is what I propose. One can not "clarify & explain" this in just a textual footnote. Graphs should help. And no, no bifurcation in play (C'mon). Once we decide to present the two-way-PT, there are consequences. Major consequence is: we must accept to show an ambiguous graph. I'm fine with that, and will push the ambiguity clarify it, graphical ways included. Go full double-form. -DePiep (talk) 23:44, 20 October 2020 (UTC)
 * Well, I agree with you that there should not be bifurcation in play. That's why I'm wary of anything that makes it look like that. But, again, we can decide all about such issues on the footnote once we've established what to show as the main thing and what to show in the footnotes. I would like to clarify the discussion flow by focusing on one thing at a time here, if that's alright with you. ^_^ Double sharp (talk) 23:54, 20 October 2020 (UTC)

Opinions
Requested from who have discussed things on the ELEM talk page recently and are still active. Double sharp (talk) 15:20, 18 October 2020 (UTC)
 * could you give a wlink or two for me to read? As in: 'this describes my approach well'? -DePiep (talk) 16:23, 18 October 2020 (UTC)
 * let me see what I can come up with. Sandbh (talk) 08:22, 19 October 2020 (UTC)


 *  Very Strong Support for Sc-Y-Lu, for reasons set out below. Briefly: IUPAC is going to make a decision, but has not done so yet, and we have no idea when they will. So I feel we should look at the fact that most sources focusing on the group 3 issue are in favour of Sc-Y-Lu and give lots of scientific arguments for why, and that this choice has gotten into a significant number of standard textbooks and popularised treatments of the periodic table for laymen. The facts that the previous IUPAC decision in favour of the compromise Sc-Y-* (now it seems to be overturned by a new project relooking at the issue) appeared to admit that Sc-Y-Lu was better as well as a minor ancillary argument in its favour in my opinion, as is the fact that the latest 32 column periodic table shown in a IUPAC Red Book is Sc-Y-Lu, but to me these are the weaker arguments. Double sharp (talk) 15:15, 18 October 2020 (UTC)
 * Support for Sc-Y-Lu. Droog Andrey (talk) 16:58, 18 October 2020 (UTC)
 * Comment moved below under YBG (talk) 02:23, 21 October 2020 (UTC)
 * Neutral, with a comment. (ec) I am neutral re Lu or La, because I cannot weight the scientific arguments & sources brought into this. However, for the encyclopedia I make this claim that "The Footnote" re group 3 be improved, and be systematically the same throughout all articles and PT templates. For example, the sup link should be the same [g3] everywhere duh. Also, there must be a wikilink to section say " Periodic table " (or whatever single point to link to), that addresses this issue from the top. Why is there no article Periodic table Group 3 issue anyway?
 * So: up to a generic and good group3[footnote] text & link. -DePiep (talk) 22:36, 18 October 2020 (UTC)
 * There's no article but there is a section: Group 3 element. Indeed, we can improve "The Footnote". EdChem and I have been discussing how to do it. ^_^ Double sharp (talk) 22:41, 18 October 2020 (UTC)
 * There once was such an article, DePiep. EdChem (talk) 22:51, 18 October 2020 (UTC)
 * Eh, don't blame me but just improve the proposal then (puh-lease). And since you both understand and agree, let's do so along the main line & intention I described. -DePiep (talk) 22:58, 18 October 2020 (UTC)
 * Not blaming anyone. Here is the merge discussion – not much participation – but I have wondered whether a stand-alone article is a sensible way forward (though a better one than the one that was merged).  EdChem (talk) 23:04, 18 October 2020 (UTC)
 * Is not my problem, is not the issue. Again, I seriously propose to make this footnote be: more to the point (spell out IUPAC, really?), the same line structure everywhere, use the same[g3] visual representation enwiki wide. So: same everywhere. -DePiep (talk) 23:24, 18 October 2020 (UTC)
 * Anyway, to keep things clear, I guess we could wait and see what consensus develops before deciding how the footnote is going to read. ^_^ I'll add a brief note above saying that the exact wording of the footnote can be subject to future discussion, but there will be one. Double sharp (talk) 00:02, 19 October 2020 (UTC)


 * Support Sc-Y-Lu for reasons mentioned in previous discussions and described here by Double sharp. I've said my piece before, and I haven't read anything or otherwise had reason to change my opinion. I simply am more convinced by the block and periodic trends arguments described for Lu-Lr in the literature; if I find what I wrote before, I will repost it. (I apologize for not having followed the whole thread.) ComplexRational (talk) 23:57, 18 October 2020 (UTC)
 * Oppose a change, at this time.
 * Briefly:
 * the relevant IUPAC committee may or may not accept the report of the Group 3 project;
 * as such, there are no plans for the relevant IUPAC committee to draft a formal recommendation and seek input from the chemistry community;
 * Sc-Y-*-** is NOT due to be deprecated—that will be matter for discussion within IUPAC as a whole, since the periodic table appearing in The Red Book is simply that used within IUAPC rather being formal recommended by IUPAC for external use; and
 * IUPAC has never decided in favour of any form of table—I’ll expand on this later.
 * More details moved below in . YBG (talk) 01:39, 23 October 2020 (UTC)
 * --- Sandbh (talk) 01:15, 21 October 2020 (UTC)
 * 's response and 's replies moved below (in ). YBG (talk) 01:39, 23 October 2020 (UTC)
 * Support Sc-Y-Lu due to: (1) more pleasing esthetics; (2) greater consistency with the Aufbau principle aka Mandelung rule, a good first-order approximation that gets stressed as orbital energy levels grow closer and then crumbles in the face of relativistic effects; (3) closeness to Janet's Left Step periodic table; (4) Apparent increasing RS support per . My opinion is swayed by (1)>(2)>(3)>(4), contrary to WP policies, but there you have it. I will loose no sleep if we keep Sc-Y-La until we know IUPAC's decision and the reaction to it. Let's reach a decision quickly, lest our energy and creativity is redirected away from WP improvements we all agree on. YBG (talk) 05:42, 19 October 2020 (UTC)
 * Well, (2) also seems like a legitimate reason; if we are going to discuss the Madelung rule in the context of the PT like many sources do, then it makes sense for the PT we display as primary to actually follow it. So, don't worry about it. ^_^ Double sharp (talk) 08:58, 19 October 2020 (UTC)
 * Support Sc-Y-Lu due to: (1) more pleasing esthetics; (2) greater consistency with the Aufbau principle aka Mandelung rule, a good first-order approximation that gets stressed as orbital energy levels grow closer and then crumbles in the face of relativistic effects; (3) closeness to Janet's Left Step periodic table; (4) Apparent increasing RS support per . My opinion is swayed by (1)>(2)>(3)>(4), contrary to WP policies, but there you have it. I will loose no sleep if we keep Sc-Y-La until we know IUPAC's decision and the reaction to it. Let's reach a decision quickly, lest our energy and creativity is redirected away from WP improvements we all agree on. YBG (talk) 05:42, 19 October 2020 (UTC)
 * Well, (2) also seems like a legitimate reason; if we are going to discuss the Madelung rule in the context of the PT like many sources do, then it makes sense for the PT we display as primary to actually follow it. So, don't worry about it. ^_^ Double sharp (talk) 08:58, 19 October 2020 (UTC)
 * Well, (2) also seems like a legitimate reason; if we are going to discuss the Madelung rule in the context of the PT like many sources do, then it makes sense for the PT we display as primary to actually follow it. So, don't worry about it. ^_^ Double sharp (talk) 08:58, 19 October 2020 (UTC)


 * If I may rain on your parade ^_^:
 * 1. What did you mean by "contrary to WP policies"?
 * 2. The Lu form is less consistent with Madelung rule, since it has 13 discrepancies compared to the 12 of the La form
 * 3. "Aesthetics" is a culturally dependent criterion and, as such, has no basis in science. Since, many folks seem to be swayed by aesthetics and symmetry, I'll start a new section about this.
 * --- Sandbh (talk) 03:49, 25 October 2020 (UTC)


 * IIIB or not IIIB? I was taught (it was when Methuselah was still a lad) that it was Y-Sc-La. IIRC, that's what Cotton & Wilkinson said. I only recently became aware of the Sc-Y-Lu suggestion through one of those Periodic Videos.
 * I have no opinion on the current scientific consensus (if any), and am not going to trawl through the citations for and against the positions. As an organic chemist, I have zero interest in the less fashionable parts of the periodic table anyway.
 * What I do know is this: WP:RS, in particular WP:SOURCETYPES. WP's voice should say what the current consensus, as described in modern editions of advanced textbooks amd review articles in respected general-interest scientific publications, is. We can (and should) describe the La/Lu debate and arguments. We should absolutely not take a position on it. That would be WP:OR. Narky Blert (talk) 19:17, 24 October 2020 (UTC)
 * First of all, thank you for your comment. I greatly appreciate your perspective as a chemist and as an experienced Wikipedian. And yes, I guessed that this is not exactly a hot-button issue among those whose specialty isn't the rare earths. ^_^ So I am going to reply to your third paragraph, which I definitely agree with, to clarify what I meant as the starter of this thread.
 * As the starter of this thread, I want to clarify that I have no intention to have WP take such a position. That's why I don't like the current situation at templates like where the La form is simply presented with absolutely no indication that there is any controversy: it feels to me too much like taking a position. Likewise I don't like what it used to show before that, which was the Lu form with no indication either. The issue extends further to places like List of chemical elements where the group for La is simply listed as "3" with no indication at all that this is controversial. I think most of us agree here that since there is a controversy that has gone up to IUPAC, WP has to reflect its existence, and not make it look like there is one agreed version when there isn't. So these two above are my proposals for how  looks, either of which I think would improve the template.
 * Out of various possible ways I considered to show the issue, I thought the two above were best, putting one option in the main table but always taking care to put a note saying that there is another. Because this way (1) the other option is always clearly presented in a footnote summarising the dispute, (2) it avoids duplicating the rest of the table which is identical, and (3) it's already in use on Polish Wikipedia, suggesting that it should not be too far off from general WP norms to do it this way. I didn't think showing 2 tables all the time was a good idea (because apart from where Sc and Y and the group 3 label appear, they are identical in every other way, and it really doesn't seem that sensible to me show 2 PT's when the PT is to be presented in an article describing, say, some topics in organic chemistry where the rare earths are of very little interest), and I also didn't think duplicating Sc and Y in one table was a good idea (because that makes a new graphic form appear that is hardly if ever used). So, that is why the options are as above: I couldn't think of anything better, and Polish Wikipedia using it made me think that English Wikipedia would probably also be fine with something like it. That being said, if you have another suggestion for how we could reflect this issue in a policy-compliant way, I should like to see and consider it! And if you don't, no worries; your comment here regarding WP:RS is already greatly appreciated by me. ^_^
 * So my question and survey here was intended to ask for opinions regarding whether it better reflects the source situation to show La as the main one and Lu in the footnote, or Lu as the main one and La in the footnote. Not which is scientifically better, which is not a question relevant for making a WP decision indeed. I thought that would be clear, but in retrospect given some issues wrt respect for policy that have arisen at the project, I should probably have made it clearer. (That's an issue I currently have with a single editor User:Sandbh, and should be if I understand correctly be discussed at the ANI thread I currently have open rather than here.) At least, I am just using "Support Sc-Y-Lu" as a shorthand for "Support showing the Lu form as primary with a footnote explaining that La sometimes appears there"; I cannot speak for the others supporting it, but I think (and hope) that that is the general idea among them too. Double sharp (talk) 21:54, 24 October 2020 (UTC)
 * Well put.
 * The most popular form of the periodic table is the one with La in group 3.
 * The Polish periodic table sort of acknowledges this too, where it notes: "Alternatively, scandlers often [italics added] include not lutetium and lorens but lanthanum, actinium and the hypothetical unbiun."
 * Possibly the reason why they show Lu in group 3 is erroneously set out in their article on the group 3 elements. This article says, in part, "IUPAC includes lutetium (Lu) and lorens (Lr) [1][2][3]." This is nonsense; IUPAC has never taken a position on group 3. None of the three listed citations say this.
 * Note the main table in their periodic table article uses the IUPAC format.
 * --- Sandbh (talk) 03:37, 25 October 2020 (UTC)
 * I thought of proposing a straw poll of Martyn Poliakoff's ties, but concluded it would be WP:OR. Narky Blert (talk) 10:46, 25 October 2020 (UTC)


 * Oppose for the time being. My reasoning can be found below.--R8R (talk) 15:42, 25 October 2020 (UTC)

Supplements
Anyone can write a long wall of text here supporting a position. I prefer the opinions above to be kept short (one paragraph of justification, maybe) to avoid confusing the issue, but here we can go on as long as we want. Double sharp (talk) 16:38, 18 October 2020 (UTC)

Long justification by DS for his !vote
When asking this, we need to look at reliable sources by policy. So what do the most reliable sources say? Here's my view. In contrast to my previous postings on it, I am not going to mention the scientific arguments at all because they are not relevant for WP: only the sources.

IUPAC

Well, there's the rub. They haven't exactly decided. Since 2015 they have had a project specifically to deliver a recommendation on which it should be. Some sporadic progress updates have been posted, but there is no indication on a time schedule. Given that IUPAC has not actually approved any form of the periodic table (link is to their website), this is maybe not surprising.

Now, it is true that they currently do show something. They show a compromise form with all fifteen lanthanoids, and all fifteen actinoids, in group 3 below yttrium. The only trouble is that if you look at their project page, this compromise is specifically not among one of the two alternatives that will be picked. All they say there is:

This project will deliver a recommendation in favor of the composition of group 3 of the periodic table as consisting either of


 * 1) the elements Sc, Y, Lu and Lr, or
 * 2) the elements Sc, Y, La and Ac.

So, what we can say is that IUPAC has acknowledged that there is an argument and has set up a process to make a decision. In my opinion that shows clearly that we should not present any one form as if it is uncontested. The only problem is whether to make it:


 * 1) Show La as default, with Lu footnoted as a version some advocate; or
 * 2) Show Lu as default, with La footnoted as a version some advocate.

We can also ask where this compromise came from. That seems to be from the 1988 IUPAC report New notations in the periodic table prepared by Ekkehard Fluck.

THE ELEMENTS OF THE SCANDIUM GROUP

In the "Red Book" which will appear in 1988 the same arrangement was chosen for the elements of the scandium group as in the periodic table as originally proposed by CNIC and subsequently published by VCH Verlagsgesellschaft, Weinheim. [This is Sc-Y-* with all fifteen lanthanoids below Y.]

It is a compromise. According to the electron configurations of the elements, the scandium group consists of the elements

Sc, Y, Lu, Lr.

This was pointed out as early as 1959 by L.D. Landau (ref. 20) and later by other authors (ref. 13, 14, 20 to 25). Most periodic tables in textbooks and classrooms, however, list Sc, Y, La, and Ac as elements of the scandium group and designate the elements Ce to Lu and Th to Lr as lanthanides and actinides, respectively. The historical background for this arrangement is given in a paper by W.B. Jensen (ref. 21). Based upon their electronic configurations and their chemical and physical properties, the elements La to Yb and Ac to No should be inserted between barium and lutetium and between radium and lawrencium or for practical reasons be listed at the bottom of the table. The series La to Yb and Ac to No then, however, cannot be named correctly as lanthanides and actinides since they contain the elements lanthanum and actinium and not only elements similar to lanthanum and actinium as is purported by the ending -ide (or -oid according to an earlier IUPAC recommendation).

The arguments for Sc-Y-Lu in the literature, judging by this, seem to have been considered convincing by an official process of IUPAC. (One may argue that Fluck prepared the report, but IUPAC also published it and others gave comments.) This is suggestive, although weak because it did not lead to its adoption. The reason for Sc-Y-* to be adopted seems to be just to compromise between this and the fact that Sc-Y-La was more common. However, that is also a bit moot because the IUPAC project is specifically not going to pick the compromise option; evidently it is not a compromise that actually made anyone arguing about this happy. So this doesn't strongly support anything very well in my opinion: surely it eventually decided in favour of showing Sc-Y-*, but apparently now this is not going to be the final decision; and surely it suggested that some people at IUPAC were convinced by Sc-Y-Lu arguments, but it didn't translate to its official acceptance. I personally read this as a point mildly in favour of us showing primarily Sc-Y-Lu over Sc-Y-La (since Sc-Y-* is due to be deprecated), but it is not the strongest one.

The report refers to the 1988 Red Book. Now, there wasn't actually one. But there was a 1990 Red Book (maybe it got delayed?), which contains 8, 18, and 32 column periodic tables. The 8 and 18 column forms shown indeed follow the compromise arrangement just as Fluck said. However, in a 32 column form this compromise is simply impossible without stretching scandium and yttrium. And lo and behold, on p. 283 it shows a 32 column table with a Sc-Y-Lu group 3. With "3, IIIA, IIIB" very clearly presented above the column with Sc, Y, Lu, and Lr, and nothing above the column with La and Ac.

The only subsequent Red Book is from 2005, and there only the 18 column form is presented: they write "Lesser omissions include ... the several different outdated versions of the periodic table." So the significance of the Sc-Y-Lu group 3 in the 1990 Red Book is in doubt, since it is for the 32 column form that they call outdated. OTOH, that 32 column form is actually still used, and our navbox templates actually show it, so it's not really that outdated. One could equally make the argument that since we show the 32 column form sometimes, and that is the latest 32 column form shown officially by IUPAC, that we should follow it. I do read this as a minor point in favour of showing primarily Sc-Y-Lu over Sc-Y-La, but again it is not the strongest one. Which is maybe not surprising because they have not recommended anything yet, so we cannot read too much into this.

A paper by Holden that was supposed to be presented to the IUPAC general assembly in 1985 clearly supports the Lu under Y option. But IUPAC has not yet officially recommended it.

Therefore, the situation with IUPAC seems to be:


 * IUPAC has not recommended any particular form of the periodic table. It plans to make a recommendation on group 3, but has not yet. It currently shows a compromise form on group 3, but clearly states that that compromise will not be its eventual recommendation. In the 18 column form it continues to use the compromise while not recommending it. A report published by them admitted that for scientific reasons lutetium in group 3 is better, but did not go on to recommend its adoption. On one occasion, when they showed the 32 column form of the table they clearly showed lutetium and not lanthanum in group 3. They later called the 32 column form outdated, but we actually do use it in some places.

This suggests to me that:
 * The compromise form, while having merit previously, has much less merit now because IUPAC has at least made it clear that it will be deprecated. Eventually.
 * Among the other two forms, lutetium in group 3 may have a very slightly greater claim to IUPAC than lanthanum in group 3 which doesn't have any, because of the statements in the report and its appearance in the 1990 Red Book. However, neither claim is all that strong because IUPAC has not made any recommendations on the PT yet.

So IUPAC isn't so helpful as it doesn't clearly support anything at the moment. All we can get from it is confirmation that the dispute exists.

Textbooks

A IUPAC survey of textbooks shows that while the La form dominated in the past, support for it significantly weakened with the start of the new millennium. We have now reached the point where it does not have a majority. Indeed, no form seems to have an overwhelming advantage anymore:

I have given percentages that were not in the original, but that is WP:CALC I guess. It's not a full-blown statistical analysis. Although the set of texts with lanthanum in group 3 is still a majority, it has significantly lost its former plurality.

Moreover, the set of texts with lutetium in group 3 has quite a few well-known texts in it (not a complete list):


 * Atkins and Jones: Chemical Principles: The Quest for Insight (2002)
 * Ball: The Elements: A Very Short Introduction (2002)
 * Brown et al.: Chemistry: The Central Science, 11th ed. (2009)
 * Ebbing et al.: General Chemistry, 9th ed. (2009; they changed from lanthanum in group 3, which they showed in the 8th ed. of 2005)
 * Jerry et al.: Techniques in Organic Chemistry, 3rd ed. (2010)
 * Metcalfe et al.: Modern Chemistry (1974 and 1982)
 * Jones and Atkins: Chemistry: Molecules, Matter, and Charge (2000)
 * Oxtoby et al.: Principles of Modern Chemistry, 8th ed. (2016; they were already showing that way back in the 1980s)
 * Rayner-Canham and Overton: Descriptive Inorganic Chemistry, 4th ed. (2006)

Excluded from the survey but also extremely well-known is
 * Clayden et al: Organic Chemistry.

There is also
 * John Emsley, Nature's Building Blocks (I don't know why this was included, as it's not a textbook, but it's a rather popular book on the elements for laymen; its adoption of Sc-Y-Lu shows that this would not be unfamiliar to the average person)

I think it's clear that the Lu form cannot be dismissed. It has to be mentioned in some fashion with such adopters. Of course, the La form also has very significant adopters, such as Greenwood and Earnshaw; I just list more Lu adopters to make it clear that these things do exist.

I draw from this situation the conclusion that:


 * Although in the past the form with lanthanum in group 3 was overwhelmingly predominant and deserved priority, this is not so clear anymore. Given such percentages, it seems clear that whatever form is eventually shown as a default, there should be some sort of footnote that makes it clear that other arrangements of group 3 are commonly encountered.

So textbooks aren't so helpful either. We can get confirmation that the dispute exists, and that we have significant names on both sides, but we still don't have any idea which should be primary.

Specific articles, texts, books, etc. focusing on the issue

We now come to what I feel is the most important argument. Probably most textbooks do not have their focus on this issue, and so it is necessary to look at articles also that do.

Probably one of the most cited articles about this is William B. Jensen's from 1982 supporting Lu. That is the one that even IUPAC referred to above. In fact even La advocates have complained about how often it is cited (e.g. Lavelle). In this article he brings together much supporting evidence from various articles by physicists and chemists. Among those that he cites are:


 * 1) Landau and Lifshitz (1958; yes, seriously, a very noted physics textbook)
 * 2) Hamilton and Jensen (1963),
 * 3) Hamilton (1965),
 * 4) Luder (1967),
 * 5) Merz and Ulmer (1967),
 * 6) Chistyakov (1968, two articles that I can't find maybe because they are in Russian)

Another source from this time period (maybe less cited) that additionally support this placement is:


 * 1) Wittig (1973),

Today, many articles focusing on the question refer to Jensen (1982) or some of his sources, such as Thyssen and Binnemans (2010) which clearly refers to Jensen (1982), or Labarca and Gonzalez (2019) which clearly refers to Jensen (1982) as well.

As can be seen from the above, this took some time to percolate into chemistry textbooks. Jensen complained in his 1982 article that chemists were at that time generally unaware of the dispute. But now it has been getting quite somewhere. In the 2000s even more articles came in, and a particularly strong voice in favour of lutetium has been Eric Scerri who chairs the IUPAC project mentioned above that is aimed at resolving this question. In recent years his rhetoric has even gone so far as saying that the paradigm of lanthanum in group 3 "must die".


 * 1) Scerri (1991)
 * 2) Scerri (2009)
 * 3) Scerri (2009)
 * 4) Scerri (2009)
 * 5) Scerri (2013)
 * 6) Scerri (2015)
 * 7) Scerri (2019)
 * 8) Scerri (2019)
 * 9) Scerri (2019)
 * 10) Scerri (2019)
 * 11) Scerri (2020)
 * 12) Scerri (2020)

In particular, note his books The Periodic Table: Its Story and Its Significance and The Periodic Table: A Very Short Introduction. Both are popular treatments and both supports the Lu under Y option.

Of course Scerri is not the only source supporting it. We also have quite a few more:


 * 1) Kulsha (1999): available on the author's website, pages 1, 2, 3, 4 (Russian) (author is User:Droog Andrey)
 * 2) Fang et al. (2000),
 * 3) Horovitz and Sârbu (2005),
 * 4) Wulfsberg (2006),
 * 5) Ouyang et al. (2008),
 * 6) Thyssen and Binnemans (2010)
 * 7) Nelson (2013)
 * 8) Settouti and Aourag (2014),
 * 9) Settouti (2015) (French)
 * 10) Tsimmerman (2018)
 * 11) Labarca and González (2019) (Spanish)
 * 12) Tsimmerman and Boyce (2019)
 * 13) Alvárez (2020)

And what of lanthanum arguments? Well, from before Jensen's 1982 article there is:


 * 1) Trifonov (1970) "Rare-earth elements and their position in the periodic system" – but he lists various arguments, some supporting Lu and some supporting La, and finally picks La on the basis of just one of them
 * 2) Shchukarev (1974) Neorganicheskaya khimiya, Vol. 2

The only ones present in specific articles or sections of books focusing on it, dating from after 1982 when Jensen brought things to chemists' rather than just physicists' attention, are those of Lavelle; Restrepo; and Vernon (= User:Sandbh).


 * 1) Lavelle (2008)
 * 2) Lavelle (2008)
 * 3) Lavelle (2009)
 * 4) Restrepo (2017, )
 * 5) Vernon (2020)

Of the last two, I cannot complain; they are legitimate reliable sources supporting Lu. But Lavelle's three articles have all been strongly rebutted by Jensen in his articles of 2008 and 2015. His verdict on Lavelle's La advocacy is particularly devastating:

But my greatest surprise came on reading the commentary itself and discovering the inconsistent reasoning and misleading distortions used by Lavelle to support his claims. ... When it comes to the question of why La and Ac should remain in the d-block rather than being reassigned to the f-block, Lavelle offers no new chemical or physical evidence other than his constant reiteration of the fact that both elements contain d-electrons in their ground-state valence configurations, but no f-electrons. Yet in the cases of both Lu and Th, for which this is equally true, he proceeds to inconsistently argue that this fact is of no consequence when it comes to assigning them to the f-block. As with the case of the revised configuration for Lr, which counts when it comes to not placing this element in the d-block but is irrelevant when it comes to placing it in the f-block, this arbitrary and naive use of electron configurations, to the exclusion of all other evidence, is logically inconsistent and leaves one with the impression that the only true argument that Lavelle has for the major premise of his diatribe is that La and Ac should remain in the d-block because that is where IUPAC places them in its official periodic table [which it does not do now and did not do then, although that is what Lavelle claimed] and therefore all rational discussion of other possibilities is strictly forbidden.|undefined

And he also points out that, contrary to Lavelle's charge that his 1982 article is outdated, the support for Lu in group 3 has significantly increased since he wrote that article, pointing to Ouyang et al. (2008) and Fang et al. (2000).

Although Jensen clearly has a stake in the matter himself as a strong Lu supporter, I feel this should be taken into consideration in some way. Disagreements where one source rebuts another's arguments are of course nothing too special (e.g. Vernon does so to Alvarez), because these are literally opposing views. But the scale of this rebuttal is pretty huge compared to Vernon's rebuttals of a few recent Lu arguments in his paper. So is its tone.

Looking at the fact that La supporters among articles that address the problem in some way are fewer in number, contain one that has gotten a very devastating rebuttal, and the fact that Lu supporters are greater in number and are having a clear effect on what textbooks show (it was slow at first but it's getting somewhere), I submit that the literature-based case is in favour of lutetium as a default. It has the support from most of the articles discussing the issue, and that has already percolated into support by some significant, established textbooks such as Clayden et al.'s Organic Chemistry (hardly fringe), as well as significant, established popular treatments of the periodic table such as Emsley's Nature's Building Blocks and Scerri's The Periodic Table: Its Story and Its Significance. This isn't just a bunch of articles saying B is true and railing against A when textbooks continue to say A in spite of them, like it would have been in the 1990s. It's a bunch of articles saying B is true and railing against A when a significant number of noted textbooks have followed them and have started to say B. And creating an argument that IUPAC has acknowledged. Note that Scerri, Jensen, Lavelle, Restrepo, and Ball are all on the IUPAC project!

That is not to say that we should sweep the whole issue under the rug and pretend that Lu has already won and gotten the IUPAC approval. Of course we shouldn't do that. But it does mean that I think the best way to deal with this situation is to present lutetium in group 3 as the main thing, and to mention in the footnote that lanthanum in group 3 is also a common placement. For a generally used template, this could be done like so as I proposed above.

That nicely reflects the situation: IUPAC hasn't yet made a decision, and the literature is undecided as a whole, but the subset of it focusing on this issue skews towards Lu in group 3. When IUPAC makes a decision, we can revisit depending on what they say and how many chemists listen to them.

Finally, insofar as that is worth something, this layout is exactly that of the 32 column form given in the IUPAC 1990 Red Book (expect that it doesn't have the colours, has the old alternative group numbers also, lacks the note on group 3, and lacks the elements past Lr which had not yet been officially named at the time). Double sharp (talk) 10:15, 18 October 2020 (UTC)


 * P.S. Ancillary argument brought to my attention by User:YBG

Although my personal inclination is already swayed by the above argument, focusing on the sources focusing on the group 3 question based on my reading of WP:CONTEXTMATTERS, User:YBG gave another argument I agree with in his !vote.

The point of that argument is that Sc-Y-Lu in group 3 is definitely more consistent with the Aufbau principle in that it clearly puts the 4f elements before the 5d elements. That is in the sense of just filling in electrons: so when trying to guess the electron configuration of erbium in the ground state, you see 68 electrons as Z = 68, and fill them in from lowest energy orbital up in the order 1s, 2s, 2p, 3s, ... demanded, and get [Xe]4f126s2 as it correctly is. This is, in general, the sense in which Aufbau is discussed: not about differentiating electrons, but about whether the total ground-state gas-phase configuration matches what happens if you do that. This is why molybdenum [Kr]4d55s1 is universally considered an Aufbau anomaly even though it has the correct 4d differentiating electron from niobium [Kr]4d45s1, because Aufbau used in the accepted sense would predict it to be [Kr]4d45s2 (which is a little bit up in energy). But technetium [Kr]4d55s2, the next element, is never considered an Aufbau anomaly even though it has the wrong 5s instead of 4d differentiating electron from molybdenum.

The argument therefore is that since it is pretty universally agreed that the Aufbau principle has something to do with the shape of the periodic table, it is significantly easier to do the sort of explanations typically found in textbooks on periodicity if one uses a Lu table. If one uses a La table, one often ends up with the "pedant's hand raised at the back of the classroom" phenomenon: one has to note that the table does not follow Madelung there, that La is the one transition metal of the third transition series that is not affected by the Ln contraction, and so on. Yes, some sources happily self-contradict (Greenwood and Earnshaw actually does it for the second issue I mentioned), but it's an easily avoidable self-contradiction. That seems to me to be a case where WP:IAR could be reasonably applicable: both La and Lu have some reasonable source-based cases going for them, but it is just easier to write the article without lurking self-contradiction to be swept under the rug if Lu is given first place. Double sharp (talk) 22:32, 6 November 2020 (UTC)

A couple of notes from before
I originally posted this as a discussion thread, but we have discussed this to death already, so I decided to turn it into a !voting thread since no one else has posted !votes / opinions yet. I posted an extremely long rationale for my !vote, but the actual question itself seems pretty neutral to me. Mostly, I just want to get this through, having discussed this topic in various iterations on WP pretty much since the year started.

Some earlier discussion took place and is below. Double sharp (talk) 15:17, 18 October 2020 (UTC)


 * Finally I note: we have already had a significant amount of support expressed for Lu in group 3 as default here. I have been strongly supporting it in the previous discussions; so has User:Droog Andrey; so has User:ComplexRational; so has User:YBG; so has User:Dreigorich (although he's since retired); so has User:Officer781. Against we have User:R8R and User:Sandbh. Now, on our side, it is true that Droog Andrey has written an article off WP supporting his favoured side, but so has Sandbh. If you subtract those, we still have a very solid majority against a minority of one. Now, it's true that previously when we were doing this the argumentation was more about the science than the sources, and we were not considering a footnote, so we do need to check with everybody (except retired Dreigorich) if the support still holds. But it is indicative I think. Double sharp (talk) 10:27, 18 October 2020 (UTC)

Forgot to ping you, sorry. Double sharp (talk) 10:47, 18 October 2020 (UTC)

One question, if I may: is the proposal only about the group 3 debate or is it also about moving the primary categorization scheme to blocks only? I had the feeling it was the former but the illustrative table uses new categories, too.--R8R (talk) 10:54, 18 October 2020 (UTC)
 * Sorry, it's just about group 3, and I grabbed the wrong PT. Excuse me while I delete it and make one that sticks to current categories and just moves Sc and Y. Double sharp (talk) 10:58, 18 October 2020 (UTC)
 * ✅ Now it shows current categories. Double sharp (talk) 11:01, 18 October 2020 (UTC)

Comment by EdChem and ensuing thread
This subsection moved from with the permission of its two contributors, as noted in. YBG (talk) 02:23, 21 October 2020 (UTC)

End of copied thread. YBG (talk) 02:23, 21 October 2020 (UTC)
 * Comment: I am not comfortable with the wording of the note. The central point, IMO, should not be about the dispute, it should be about the science.  I think the note should focus on the fact that La, Ac, Lu, and Lr each have properties that are consistent with grouping them with the inner transition metals or with the transition metals, and that there are reasonable arguments for both classifications.  As any element appears only once on the PT, a choice needs to be made as to how to position them.  IUPAC have a working group, which has yet to report its recommendation, that will be used to provide an official position.  Even once this occurs, however, it will need to be recognised that the properties of these elements will be more typical of the alternative placement.  This is obviously too long but I suggest that the feeling of this is more appropriate – that the science supports different interpretations rather than the scientists are having an argument because of (whatever)... when I read the NB this morning, I thought of how we can say that "whether coronavirus is a major health threat or a triviality being scaremongered by evil people who don't agree with individual X (whoever that is) is under dispute in the American community."  An imperfect analogy, obviously, but the point is not that there is a dispute but that there is a reasonable basis in science for it.  For readers, knowing that the properties of the elements are not always consistent with their position on the PT is valuable information, IMO. EdChem (talk) 21:26, 18 October 2020 (UTC)
 * Aside – A request: Please can we keep !voting to simple support / oppose with reasons? A support is weighted more highly in a consensus discussion because of the quality of the evidence presented or policy rationale, etc... it is not weighted more highly because of the strength with which the view is held.  I super-dooper mega-support with a cherry on top that there should be a law against mornings, but that doesn't make it any more likely.  Thank you.  EdChem (talk) 21:26, 18 October 2020 (UTC)
 * OK, changed to just a plain support by striking out "very strong". ^_^
 * I'm totally OK with changing the note's wording! The only thing I feel strongly about here is that Lu should be the primary option shown and that La should be the one mentioned in a footnote. And even for that, I will bow to whether consensus ends up for it or not. Exactly how the footnote should be worded is something where I agree my current option can be improved. ^_^
 * So far as I can see, the different scientists involved in this disagree on exactly which properties are important for periodic table placement, and exactly how those properties should be interpreted. On the first, you can see the argument about whether electron configuration or chemistry is most important for placement. The second is why you can sometimes see the exact same property being pointed to both by La supporters and Lu supporters as evidence for their position. So maybe that's an OK summary to be added to the note: "The disagreement is based on which properties should have most significance for periodic table placement and how those properties should be interpreted for that purpose", to be added as a middle sentence. Or something like that, I'm writing quickly and it's probably not the best wording, but maybe it will serve as another idea that can be improved on. Hopefully that is not summarising so far that it becomes OR intepretation, though. If you like the improved note, I can add it, although I worry that it may muddy the waters of who is supporting what and whether opposition is against the footnote or against the choice of Lu primary + La footnote.
 * As for what happens after IUPAC makes its decision, I think I would rather look at the situation then. It's possible that they make a decision and everyone accepts it and the other option dies out outside historical texts. It's also possible that they make a decision and a lot of people protest against it and we end up in a situation where IUPAC has made a decision that is vocally disputed and that a significant number of chemists don't follow. And it's also possible for something in between total instant acceptance and instant strong protests. Each of those situations will require us to reflect things differently; the footnote might be able to vanish in the first case, but certainly not in the second. So I prefer to wait and see how the situation evolves after the decision happens and see whether we need a footnote then and if so, what it should say; for now I'd rather focus on the situation now.
 * P.S. I agree totally with your last sentence. ^_^ Double sharp (talk) 22:23, 18 October 2020 (UTC)
 * I should remember to ping more often, sorry. Double sharp (talk) 22:26, 18 October 2020 (UTC)
 * Looks like the footnote-text needs discussion, but develop this in a separate thread? Makes it easier to follow the science/encyclopedic discussions here. -DePiep (talk) 16:39, 20 October 2020 (UTC)
 * For sure, it can be discussed in a separate thread how the footnote should read. I would like to keep the separate issues separate too, as it would probably help clarify the flow of discussions. Double sharp (talk) 18:34, 20 October 2020 (UTC)

Details of Sandbh's opinion and ensuing thread
This subsection moved from above (in ) with the permission of as noted in.


 * Rather, a (politically-charged) project sponsored by IUPAC will deliver a report and make a recommendation. At this point, IUPAC will consider whether or not to provisionally accept the report. If they don’t, the report will die. If they do, the report will presumably go out to at least the chemistry community for feedback. Once the consultation period has closed IUPAC will consider the comments. At that time, they may decide to ignore the report, or start the process of turning it into an IUPAC recommendation.
 * On sources: Most of those focusing on the group 3 issue, and finding in favour of Sc-Y-Lu, are based on single arguments. This is unscientific. In contrast, Jensen (for example) attempted a multi-argument approach. His work failed to gain traction since, as Scerri, mentioned, Jensen was too selective in his arguments (Scerri & Parsons 2018, p. 143; Scerri 2020, p. 394).
 * In contrast, the Russian author Trifonov (1970) considered several arguments, and found in favour of La.
 * There are far fewer sources arguing in favour of Lu simply because La is the accepted standard; effectively no one has been convinced by the Lu arguments; and effectively no one has seen the need to argue for La.
 * The big three i.e. G&E, C&W, and Wiberg, are unanimous in their depiction of La in group 3.
 * Scerri's view: Scerri, who is chair of the Group 3 project, concluded that arguments based on physical, chemical and electronic properties are inconclusive (Scerri 2020, p. 381). He acknowledges La is the most common form (Scerri 2020a, p. 10).
 * On sources (cont.): My article (Vernon 2020, published online 24 Sep) is the first to step back from the minutiae of physical, chemical, and electronic properties and explore considerations of regularity and symmetry, natural kinds, quantum mechanics, and philosophy. It concludes with a series of ten interlocking arguments, supporting La, in the context of a chemistry-based periodic table. This article was subjected to three peer reviews. Scerri is the the journal editor.
 * Textbooks: Like Double sharp said, Lu has gotten into an appreciable number of textbooks. The IUPAC survey (1970s to 2010s) sampled 193 of these. The count was La 130; *-** 33; Lu 30 i.e. about 4: 1: 1 in favour of La. For Lu, 30 out of 193 is appreciable, and worth mentioning, and nothing to write home about.
 * More: I'll elaborate in the Supplements section.
 * Scerri's view: Scerri, who is chair of the Group 3 project, concluded that arguments based on physical, chemical and electronic properties are inconclusive (Scerri 2020, p. 381). He acknowledges La is the most common form (Scerri 2020a, p. 10).
 * On sources (cont.): My article (Vernon 2020, published online 24 Sep) is the first to step back from the minutiae of physical, chemical, and electronic properties and explore considerations of regularity and symmetry, natural kinds, quantum mechanics, and philosophy. It concludes with a series of ten interlocking arguments, supporting La, in the context of a chemistry-based periodic table. This article was subjected to three peer reviews. Scerri is the the journal editor.
 * Textbooks: Like Double sharp said, Lu has gotten into an appreciable number of textbooks. The IUPAC survey (1970s to 2010s) sampled 193 of these. The count was La 130; *-** 33; Lu 30 i.e. about 4: 1: 1 in favour of La. For Lu, 30 out of 193 is appreciable, and worth mentioning, and nothing to write home about.
 * More: I'll elaborate in the Supplements section.
 * Textbooks: Like Double sharp said, Lu has gotten into an appreciable number of textbooks. The IUPAC survey (1970s to 2010s) sampled 193 of these. The count was La 130; *-** 33; Lu 30 i.e. about 4: 1: 1 in favour of La. For Lu, 30 out of 193 is appreciable, and worth mentioning, and nothing to write home about.
 * More: I'll elaborate in the Supplements section.
 * More: I'll elaborate in the Supplements section.
 * More: I'll elaborate in the Supplements section.


 * References
 * Scerri E 2020: The Periodic Table: Its story and significance, 2nd ed., Oxford University Press, New York
 * —— 2020a: Recent attempts to change the periodic table. Phil. Trans. R. Soc. A 378: 20190300,
 * Scerri ER, Parsons W 2018: What elements belong in Group 3 of the periodic table? In: E Scerri, G Restrepo (eds.) Mendeleev to Oganesson: A multidisciplinary perspective on the periodic table, pp. 140–151, Oxford University Press, New York
 * Trifonov DN 1970: Rare-earth elements and their position in the periodic system. Translated from the 1966 Russian edition, Academy of Sciences of the USSR Institute of the History of Natural Sciences and Technology, Moscow. Published for the Atomic Energy Commission and the National Science Foundation, Washington, by the Indian National Scientific Documentation Centre.


 * --- Sandbh (talk) 01:15, 21 October 2020 (UTC)

End of details of 's opinion moved from above (in ). YBG (talk) 01:39, 23 October 2020 (UTC)

This subsection moved from above (in ) with the permission of its two contributors as noted in. YBG (talk) 01:39, 23 October 2020 (UTC)


 * I am not convinced by this.
 * While it is true that IUPAC will not necessarily make a decision, there is no denying that it has a project that has the intention of doing so;
 * The project has no decision-making power. Rather, it’s recommendation will considered by the relevant IUPAC committee, who will decide (or not) what to do with it, as I explained. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * There are clearly plans for a IUPAC recommendation, because the project explicitly says "This project will deliver a recommendation in favor of the composition of group 3 of the periodic table as consisting either of the elements Sc, Y, Lu and Lr, or the elements Sc, Y, La and Ac";
 * Yes, the project will deliver a recommendation, which may or may not see the light of day and which may or may not be acted upon, along the lines I have explained. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Since Sc-Y-* is not one of the two options listed, it stands to reason that there must be some sort of plan to deprecate Sc-Y-* by the project if and when it should succeed in making a decision that gets approved;
 * There is no such plan since that would not be within the scope of the project. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * I have never stated that IUPAC has decided in favour of any form of table. In fact I explicitly stated that it has not. That does not change the fact that it set up a project aiming to give a recommendation on group 3. It seems completely reasonable that this means that there is some intention, in some part of it, to decide in favour of a particular form of group 3 and nothing else.
 * There is no such intention. IUPAC does not turn upon the recommendation of a single project. Don’t mistake sponsorship of one project to mean broad IUPAC endorsement, nor an intent, necessarily, to act. I addressed what is more likely to happen from the IUPAC perspective in my article. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * I don't know of any reliable source that calls the project "politically charged". Given that in contains both Scerri and Jensen (strong Lu advocates) as well as Lavelle and Restrepo (strong La advocates), one would think that its composition (those four, plus Ball and Ohrstrom) was specifically chosen to be as neutral as possible. The closest I am aware of is Scerri's complaint here where he complains:
 * There is no such plan since that would not be within the scope of the project. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * I have never stated that IUPAC has decided in favour of any form of table. In fact I explicitly stated that it has not. That does not change the fact that it set up a project aiming to give a recommendation on group 3. It seems completely reasonable that this means that there is some intention, in some part of it, to decide in favour of a particular form of group 3 and nothing else.
 * There is no such intention. IUPAC does not turn upon the recommendation of a single project. Don’t mistake sponsorship of one project to mean broad IUPAC endorsement, nor an intent, necessarily, to act. I addressed what is more likely to happen from the IUPAC perspective in my article. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * I don't know of any reliable source that calls the project "politically charged". Given that in contains both Scerri and Jensen (strong Lu advocates) as well as Lavelle and Restrepo (strong La advocates), one would think that its composition (those four, plus Ball and Ohrstrom) was specifically chosen to be as neutral as possible. The closest I am aware of is Scerri's complaint here where he complains:
 * There is no such intention. IUPAC does not turn upon the recommendation of a single project. Don’t mistake sponsorship of one project to mean broad IUPAC endorsement, nor an intent, necessarily, to act. I addressed what is more likely to happen from the IUPAC perspective in my article. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * I don't know of any reliable source that calls the project "politically charged". Given that in contains both Scerri and Jensen (strong Lu advocates) as well as Lavelle and Restrepo (strong La advocates), one would think that its composition (those four, plus Ball and Ohrstrom) was specifically chosen to be as neutral as possible. The closest I am aware of is Scerri's complaint here where he complains:
 * I don't know of any reliable source that calls the project "politically charged". Given that in contains both Scerri and Jensen (strong Lu advocates) as well as Lavelle and Restrepo (strong La advocates), one would think that its composition (those four, plus Ball and Ohrstrom) was specifically chosen to be as neutral as possible. The closest I am aware of is Scerri's complaint here where he complains:
 * I don't know of any reliable source that calls the project "politically charged". Given that in contains both Scerri and Jensen (strong Lu advocates) as well as Lavelle and Restrepo (strong La advocates), one would think that its composition (those four, plus Ball and Ohrstrom) was specifically chosen to be as neutral as possible. The closest I am aware of is Scerri's complaint here where he complains:


 * Yes, no organisation or project likes to air its dirty washing. There is nothing more I can say about Scerri’s complaint. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * (cont.) Here there is only an analogy being drawn to politics, and he does not explicitly refer to the project that he himself is chairing. One can guess, and perhaps be right, or perhaps be wrong. But that is moot because the source doesn't say it.
 * I don't know of any reliable source that considers "single-argument" sources to be "unscientific". Since the dispute is partly about what properties are significant for periodic table placement, it is a perfectly scientific and respectable opinion that one criterion is enough to decide the matter. In the 1988 IUPAC report that I mentioned as the source of the * compromise, it was stated that according to electronic configurations as well as according to physical and chemical properties the Lu table was the correct one, and they cited some of those single-argument sources for that statement. "According to the electron configurations of the elements, the scandium group consists of the elements Sc, Y, Lu, Lr. This was pointed out as early as 1959 by L.D. Landau (ref. 20) and later by other authors (ref. 13, 14, 20 to 25)." They just didn't recommend it.
 * In science there is something called triangulation, or better. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * The 1988 IUPAC paper is a good example of a low quality report that got all the attention that it deserved (basically nothing). I addressed Landau et al. in my article. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Moreover, Jensen's paper in fact collects together some of those "single-argument" sources' arguments and cites them (e.g. Merz and Ulmer, Hamilton and Jensen). It seems very strange to suggest that those arguments were "unscientific" when they were first presented separately, but that they suddenly became "scientific" when Jensen decided to republish them together in one paper, with no actual changes to them. This and the previous point show that the reservation that "single-argument" sources are "unscientific" is not necessarily shared by all scientists.
 * Jensen has a good go at triangulation plus. A few people noticed his efforts. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Finally, while Scerri did indeed think Jensen's arguments were too selective in the work Sandbh mentions, in those very same pieces he comes out in favour of Lu for different reasons; his "don't split the d block" argument and his "Madelung rule" argument. While he has later retracted the latter argument in a personal communication to Sandbh, he has never done so for the first one. Not to mention that personal communications are by definition not verifiable. There is no reason why different proponents of the same format should agree on absolutely everything. Jensen criticises triads, with Scerri uses; Scerri criticises the properties which Jensen uses; but they both are agreed on the Lu table.
 * I addressed the split d-block argument in my article. My pers. comm. cite was reviewed by three peers; as the editor, Scerri read it too, pre-publication. And it's still there. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Saying that Jensen's work "failed to gain traction", when it has at least 61 citations, when a significant number of textbooks have started showing the Lu form, when popular resource WebElements shows Sc-Y-Lu and explicitly cited Jensen for why, when you can easily find popular-science books in bookstores like Emsley's Nature's Building Blocks and Scerri's The Periodic Table: Its Story and Its Significance which use the Sc-Y-Lu form, and when Lavelle complained that "In fact the Jensen 1982 paper (6) is often considered the one and only reference needed for continued justification of their group 3 (IIIB) d-block placement in the periodic table", seems rather odd.
 * A few people notice Jensen. If he would’ve gained traction there’d be no need for an IUPAC project on Group 3. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Trifonov is one of many sources, and I mentioned it. It is also from 1970, whereas many of the sources supporting Lu under Y are significantly more recent.
 * Today a sizeable minority of textbook writers have been convinced by the Lu arguments enough to show Lu tables, reaching 23% in the 2000s and 18% in the 2010s (the dip is because of an increase in the * compromise form, which IUPAC shows even though it does not recommend; the percentage of the La form in fact dropped in this time). That's hardly "effectively no one". Counting this as 30 out of 193 lumps together textbooks from the 1970s to the 2010s. This seems inadvisable because the scientific acceptance of the Lu under Y table changed significantly during this period, with many of the papers mentioned being published then. The percentage of La under Y tables changed from 82% in the 1990s to 48% in the 2010s, but if we lump all decades together the prevalence of La gets pushed up by older and less up-to-date sources from the 1970s, 1980s, and 1990s.
 * Like I said, the chair of the IUPAC project has said that the La form is the most popular. The Lu form is no more popular than the *-** form. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Sandbh makes a reasonable point that the sources would skew towards Lu because La was standard and no one would have felt the need to defend it. But that only applies to the era when La was an "accepted standard", and the current percentage of 48% of textbooks in the 2010s is not exactly an "accepted standard". It is not even a majority. Once enough people started advocating the Lu table, and enough textbooks moved away from it, there did indeed arise a rearguard action trying to support the La table: see p. 135 of The Periodic Table: A Very Short Introduction by Scerri (2019). So we can look at the percentages from 2008 onwards (date of Lavelle's 2008 article) when this had started happening. Out of the sources from 2008 onwards that I collected, adding Jensen's three follow-up papers, we have twenty-four supporting Lu under Y, and only five (Lavelle ×3, Restrepo, Vernon) supporting La under Y. With Lavelle's papers having been given blistering rebuttals by Jensen. (A scientific disagreement is par for the course, but if Jensen goes so far as to claim that Lavelle's commentary "contains a serious distortion of the contents of [his] original article dealing with this subject", that's something quite significant IMHO.) And in the 2010s the La table for the first time lost its textbook majority and the IUPAC project was established. So we see that even when the La proponents do feel that they are under enough threat that they have to defend themselves, they still don't have a majority. In textbooks they lost it, and in articles they are not even close to it.
 * The big three Sandbh mentioned are great textbooks, but not the only ones around. In organic chemistry, Clayden is on that level, and it shows a Lu table. Not to mention that Cotton & Wilkinson, one of those "big three" textbooks, has in the 4th edition a Sc-Y-Lu partial table on p. 7, while at the same time saying that La is in "Transition Group III" in p. 981, which is not exactly consistent.
 * This is an inorganic chemistry matter. Clayden’s book on Organic Chemistry effectively means nothing. C&W are up to their 6th 1999 ed. I don’t know what the relevance of their 4th 1980 edition is. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * It is true that Scerri sees arguments based on physical, chemical and electronic properties as inconclusive. And it is also true that he admits that the La form is the most common one. But it is equally true that Scerri himself has been a fervent supporter of the Lu form since the 1990s and has been writing perhaps more articles in favour of it than anyone else.
 * Yes, and he recognises the distinction between his personal views and his views/role as the chair of the IUPAC project. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Sandbh's published article is simply one source among many others.
 * Not really. As, I said, it is the first to take a philosophical perspective, and one not bogged down in what Eric regards as minutiae. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Therefore I am not convinced by Sandbh's points. In general, I feel that they overestimate the significance of La-supporting sources and underestimate that of Lu-supporting sources, and I feel that in particular Scerri is being read selectively, and a definition of "unscientific" that is far broader than what scientists seem to use is being adopted, in order to do that. In fact, the way only parts of Scerri's articles are referred to, containing his argument that Jensen was being too selective and his admission that La is more common, but the other parts of the same articles where Scerri (and in one case Scerri with Parsons) supports Jensen's Lu stand for his own reasons are ignored, troubles me greatly. Because that means putting only part of Scerri's view under a paragraph headed "Scerri's view", and ignoring the part that is strongly in favour of Sc-Y-Lu that Sandbh is opposing. And hopefully I have kept this statement of disagreement content-based and not personal; if not, I can do some rewording. Double sharp (talk) 09:31, 21 October 2020 (UTC)
 * Since I posted on 7 Oct about the ACS Inorganic Chemistry Division, and their return to using a 32-column La logo, that is still their practice. Sandbh (talk) 11:39, 22 October 2020 (UTC)
 * . Quick comment. You only know what has been publicity released (≤20%). You know nothing about organisational politics (the 80% under the water, like an iceberg). I know more than I can disclose since, if I did so disclose, my sources would dry up. Even with what you know about what was has been publicly released you are reading things into this that have no demonstrable basis in anything, aside from wishful thinking. I'll see what I can add to my quick comments, a bit later on. Thanks. Sandbh (talk) 06:52, 22 October 2020 (UTC)
 * And why should we consider what has not been publicly released when it is by definition not verifiable? Double sharp (talk) 08:35, 22 October 2020 (UTC)
 * . Because we are project members who are committed to a common purpose, who bring gifts differing to our collective endeavours, and who hold each other accountable for our successes (or not), rather than citing WP:POLICY. How do you see that? Sandbh (talk) 09:59, 22 October 2020 (UTC)
 * Let me clarify. I don't see any "wishful thinking" in what I wrote. It seems to either be based on what was written in the reliable sources, or at least a totally reasonable inference from them. The others may wish to comment on that, though. Based on WP:V, whatever is not publicly disclosed is not something we can reflect because nobody else can verify it. So even in the hypothetical extreme situation that what the website of the IUPAC project has to say about its goals are completely wrong, and the real one is not publicly released, we have to reflect what is publicly said. Double sharp (talk) 08:49, 22 October 2020 (UTC)
 * Like I said, the chair of the IUPAC project has said that the La form is the most popular. The Lu form is no more popular than the *-** form. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Sandbh makes a reasonable point that the sources would skew towards Lu because La was standard and no one would have felt the need to defend it. But that only applies to the era when La was an "accepted standard", and the current percentage of 48% of textbooks in the 2010s is not exactly an "accepted standard". It is not even a majority. Once enough people started advocating the Lu table, and enough textbooks moved away from it, there did indeed arise a rearguard action trying to support the La table: see p. 135 of The Periodic Table: A Very Short Introduction by Scerri (2019). So we can look at the percentages from 2008 onwards (date of Lavelle's 2008 article) when this had started happening. Out of the sources from 2008 onwards that I collected, adding Jensen's three follow-up papers, we have twenty-four supporting Lu under Y, and only five (Lavelle ×3, Restrepo, Vernon) supporting La under Y. With Lavelle's papers having been given blistering rebuttals by Jensen. (A scientific disagreement is par for the course, but if Jensen goes so far as to claim that Lavelle's commentary "contains a serious distortion of the contents of [his] original article dealing with this subject", that's something quite significant IMHO.) And in the 2010s the La table for the first time lost its textbook majority and the IUPAC project was established. So we see that even when the La proponents do feel that they are under enough threat that they have to defend themselves, they still don't have a majority. In textbooks they lost it, and in articles they are not even close to it.
 * The big three Sandbh mentioned are great textbooks, but not the only ones around. In organic chemistry, Clayden is on that level, and it shows a Lu table. Not to mention that Cotton & Wilkinson, one of those "big three" textbooks, has in the 4th edition a Sc-Y-Lu partial table on p. 7, while at the same time saying that La is in "Transition Group III" in p. 981, which is not exactly consistent.
 * This is an inorganic chemistry matter. Clayden’s book on Organic Chemistry effectively means nothing. C&W are up to their 6th 1999 ed. I don’t know what the relevance of their 4th 1980 edition is. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * It is true that Scerri sees arguments based on physical, chemical and electronic properties as inconclusive. And it is also true that he admits that the La form is the most common one. But it is equally true that Scerri himself has been a fervent supporter of the Lu form since the 1990s and has been writing perhaps more articles in favour of it than anyone else.
 * Yes, and he recognises the distinction between his personal views and his views/role as the chair of the IUPAC project. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Sandbh's published article is simply one source among many others.
 * Not really. As, I said, it is the first to take a philosophical perspective, and one not bogged down in what Eric regards as minutiae. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Therefore I am not convinced by Sandbh's points. In general, I feel that they overestimate the significance of La-supporting sources and underestimate that of Lu-supporting sources, and I feel that in particular Scerri is being read selectively, and a definition of "unscientific" that is far broader than what scientists seem to use is being adopted, in order to do that. In fact, the way only parts of Scerri's articles are referred to, containing his argument that Jensen was being too selective and his admission that La is more common, but the other parts of the same articles where Scerri (and in one case Scerri with Parsons) supports Jensen's Lu stand for his own reasons are ignored, troubles me greatly. Because that means putting only part of Scerri's view under a paragraph headed "Scerri's view", and ignoring the part that is strongly in favour of Sc-Y-Lu that Sandbh is opposing. And hopefully I have kept this statement of disagreement content-based and not personal; if not, I can do some rewording. Double sharp (talk) 09:31, 21 October 2020 (UTC)
 * Since I posted on 7 Oct about the ACS Inorganic Chemistry Division, and their return to using a 32-column La logo, that is still their practice. Sandbh (talk) 11:39, 22 October 2020 (UTC)
 * . Quick comment. You only know what has been publicity released (≤20%). You know nothing about organisational politics (the 80% under the water, like an iceberg). I know more than I can disclose since, if I did so disclose, my sources would dry up. Even with what you know about what was has been publicly released you are reading things into this that have no demonstrable basis in anything, aside from wishful thinking. I'll see what I can add to my quick comments, a bit later on. Thanks. Sandbh (talk) 06:52, 22 October 2020 (UTC)
 * And why should we consider what has not been publicly released when it is by definition not verifiable? Double sharp (talk) 08:35, 22 October 2020 (UTC)
 * . Because we are project members who are committed to a common purpose, who bring gifts differing to our collective endeavours, and who hold each other accountable for our successes (or not), rather than citing WP:POLICY. How do you see that? Sandbh (talk) 09:59, 22 October 2020 (UTC)
 * Let me clarify. I don't see any "wishful thinking" in what I wrote. It seems to either be based on what was written in the reliable sources, or at least a totally reasonable inference from them. The others may wish to comment on that, though. Based on WP:V, whatever is not publicly disclosed is not something we can reflect because nobody else can verify it. So even in the hypothetical extreme situation that what the website of the IUPAC project has to say about its goals are completely wrong, and the real one is not publicly released, we have to reflect what is publicly said. Double sharp (talk) 08:49, 22 October 2020 (UTC)
 * Not really. As, I said, it is the first to take a philosophical perspective, and one not bogged down in what Eric regards as minutiae. Sandbh (talk) 11:21, 22 October 2020 (UTC)
 * Therefore I am not convinced by Sandbh's points. In general, I feel that they overestimate the significance of La-supporting sources and underestimate that of Lu-supporting sources, and I feel that in particular Scerri is being read selectively, and a definition of "unscientific" that is far broader than what scientists seem to use is being adopted, in order to do that. In fact, the way only parts of Scerri's articles are referred to, containing his argument that Jensen was being too selective and his admission that La is more common, but the other parts of the same articles where Scerri (and in one case Scerri with Parsons) supports Jensen's Lu stand for his own reasons are ignored, troubles me greatly. Because that means putting only part of Scerri's view under a paragraph headed "Scerri's view", and ignoring the part that is strongly in favour of Sc-Y-Lu that Sandbh is opposing. And hopefully I have kept this statement of disagreement content-based and not personal; if not, I can do some rewording. Double sharp (talk) 09:31, 21 October 2020 (UTC)
 * Since I posted on 7 Oct about the ACS Inorganic Chemistry Division, and their return to using a 32-column La logo, that is still their practice. Sandbh (talk) 11:39, 22 October 2020 (UTC)
 * . Quick comment. You only know what has been publicity released (≤20%). You know nothing about organisational politics (the 80% under the water, like an iceberg). I know more than I can disclose since, if I did so disclose, my sources would dry up. Even with what you know about what was has been publicly released you are reading things into this that have no demonstrable basis in anything, aside from wishful thinking. I'll see what I can add to my quick comments, a bit later on. Thanks. Sandbh (talk) 06:52, 22 October 2020 (UTC)
 * And why should we consider what has not been publicly released when it is by definition not verifiable? Double sharp (talk) 08:35, 22 October 2020 (UTC)
 * . Because we are project members who are committed to a common purpose, who bring gifts differing to our collective endeavours, and who hold each other accountable for our successes (or not), rather than citing WP:POLICY. How do you see that? Sandbh (talk) 09:59, 22 October 2020 (UTC)
 * Let me clarify. I don't see any "wishful thinking" in what I wrote. It seems to either be based on what was written in the reliable sources, or at least a totally reasonable inference from them. The others may wish to comment on that, though. Based on WP:V, whatever is not publicly disclosed is not something we can reflect because nobody else can verify it. So even in the hypothetical extreme situation that what the website of the IUPAC project has to say about its goals are completely wrong, and the real one is not publicly released, we have to reflect what is publicly said. Double sharp (talk) 08:49, 22 October 2020 (UTC)
 * And why should we consider what has not been publicly released when it is by definition not verifiable? Double sharp (talk) 08:35, 22 October 2020 (UTC)
 * . Because we are project members who are committed to a common purpose, who bring gifts differing to our collective endeavours, and who hold each other accountable for our successes (or not), rather than citing WP:POLICY. How do you see that? Sandbh (talk) 09:59, 22 October 2020 (UTC)
 * Let me clarify. I don't see any "wishful thinking" in what I wrote. It seems to either be based on what was written in the reliable sources, or at least a totally reasonable inference from them. The others may wish to comment on that, though. Based on WP:V, whatever is not publicly disclosed is not something we can reflect because nobody else can verify it. So even in the hypothetical extreme situation that what the website of the IUPAC project has to say about its goals are completely wrong, and the real one is not publicly released, we have to reflect what is publicly said. Double sharp (talk) 08:49, 22 October 2020 (UTC)
 * Let me clarify. I don't see any "wishful thinking" in what I wrote. It seems to either be based on what was written in the reliable sources, or at least a totally reasonable inference from them. The others may wish to comment on that, though. Based on WP:V, whatever is not publicly disclosed is not something we can reflect because nobody else can verify it. So even in the hypothetical extreme situation that what the website of the IUPAC project has to say about its goals are completely wrong, and the real one is not publicly released, we have to reflect what is publicly said. Double sharp (talk) 08:49, 22 October 2020 (UTC)
 * Let me clarify. I don't see any "wishful thinking" in what I wrote. It seems to either be based on what was written in the reliable sources, or at least a totally reasonable inference from them. The others may wish to comment on that, though. Based on WP:V, whatever is not publicly disclosed is not something we can reflect because nobody else can verify it. So even in the hypothetical extreme situation that what the website of the IUPAC project has to say about its goals are completely wrong, and the real one is not publicly released, we have to reflect what is publicly said. Double sharp (talk) 08:49, 22 October 2020 (UTC)

End of 's response and 's replies moved from above (in ). YBG (talk) 01:39, 23 October 2020 (UTC)

Discussion on YBG's reasons for supporting Lu
YBG's post, hereunder, as copied from here.


 * "Support Sc-Y-Lu due to: (1) more pleasing esthetics; (2) greater consistency with the Aufbau principle aka Mandelung rule, a good first-order approximation that gets stressed as orbital energy levels grow closer and then crumbles in the face of relativistic effects; (3) closeness to Janet's Left Step periodic table; (4) Apparent increasing RS support per . My opinion is swayed by (1)>(2)>(3)>(4), contrary to WP policies, but there you have it. I will loose no sleep if we keep Sc-Y-La until we know IUPAC's decision and the reaction to it. Let's reach a decision quickly, lest our energy and creativity is redirected away from WP improvements we all agree on. YBG (talk) 05:42, 19 October 2020 (UTC)"

If I may rain on your parade ^_^:
 * 1. What did you mean by "contrary to WP policies"?
 * 2. The Lu form is less consistent with Madelung rule, since it has 13 discrepancies compared to the 12 of the La form
 * 3. "Aesthetics" is a culturally dependent criterion and, as such, has no basis in science. Since, many folks seem to be swayed by aesthetics and symmetry, I started a new section about this.
 * --- thank you, Sandbh (talk) 03:49, 25 October 2020 (UTC)
 * By "contrary to WP policy", I mean that by my understanding, WP policy does not allow us to make such content decisions based on esthetics (my 1), nor on consistency with Aufbau (my 2) nor Janet (my 3) except to the extent that such esthetics or consistencies are WP:DUEly represented in WP:RSs. I was laying my hand on the table for everyone to see its weakness, acknowledging that my only reason anchored in RS (my 4) was the lowest on my list. Hence, I said, "contrary to WP policies, but there you have it". Perhaps if I had expressed myself more clearly, you might have included your 16K word essay in its own ==section== and simply included a wikilink to it. I think that would actually have strengthened your case (and not just esthetically) [irony intentional]. YBG (talk) 09:50, 25 October 2020 (UTC)

R8R's considerations
Luckily, by the time I found enough spare time to write down a response, the most prominent supporters of both versions have spoken up.

Double sharp's position amounts to a few key points:
 * D1) IUPAC's recommendations are not conclusive;
 * D2) Textbook usage analysis is not conclusive;
 * D3) Texts that tackle this particular problem clearly favor -Lu-Lr.

Sandbh's position boils down to the following points:
 * S1) Most -Lu-Lr apologists have bad arguments;
 * S2) There are few visible -La-Ac apologists because there is little reason for them to speak up;
 * S3) Scerri says -La-Ac is the most common form;
 * S4) -La-Ac has a noticeable majority in textbooks published since 1970.

I do not entirely agree with either line of reasoning.


 * D1) I agree with Double sharp that IUPAC's recommendations are inconclusive.
 * D2) I would not be so quick to discard the textbook usage, however. Even the 2010s shows a noticeable plurality for -La-Ac, which beats -Lu-Lr 3 to 1. The 2000s show a majority for -La-Ac, which again beats -Lu-Lr almost 3 to 1. I will consider the data before 2000 outdated and not relevant. Textbook analysis clearly indicates that -La-Ac is the preferred option, even if one can consider this indication not decisive.
 * D3) I mostly agree with DS. I do have the feeling, however, that this argument in itself very strong. Most of sources presented are research articles, and most argue for a change towards -Lu-Lr. For a tertiary source such as our encyclopedia, it should rather matter that sources that mention group 3 more often than not go for -La-Ac; we shouldn't add momentum to such a change, merely point out what the default version is, and even some of those -Lu-Lr sources admit it's -La-Ac.


 * S1) That may or may not be true, but that is irrelevant because we are not doing science here and casting our judgment on what Mother Nature is; as a tertiary source, we merely reflect what reliable sources say.
 * S2) That may or may not be true, but that is equally irrelevant. Either it's in reliable sources or it isn't; the former counts, the latter doesn't.
 * S3) I agree with this statement and its implications.
 * S4) I would say that 1970s or 80s are increasingly irrelevant, but I agree with the general point since recent sources (from 2000 onward) still prefer -La-Ac.

Given that we are a tertiary source, a phrase I used a number of times over the last few weeks, I believe the arguments still show there hasn't been a game changer (one may consider a possible future resolution of the IUPAC group 3 project in favor of -Lu-Lr such a game changer), and we should stick to -La-Ac for the time being, as much as I would have personally preferred to pick the other option.--R8R (talk) 15:40, 25 October 2020 (UTC)


 * Thanks for your response; I have noted it, and agree with your characterisation of my line of reasoning. Even though I don't agree, I respect your position and its base on how WP should be a tertiary source. And I also greatly respect how you decided on your choice based on what WP is even though you personally prefer the other option.
 * Can I clarify with you: would you support a general footnote whenever the precise composition of group 3 appears, even with La as the up-front option? Or would you prefer it the way it is now at with no such thing? Personally I think that with no footnote it goes too far and hides the controversy that exists, but I'm ready to hear your source-based opinions. ^_^
 * Now, I'll just comment based on the source thing.
 * I can agree with your characterisation of the textbook situation (D2); La is still more common, just not decisively so. My worry is exactly how relevant this is. Cotton and Wilkinson 4th edition had no qualms both speaking in terms of the La table and also at one point using a Lu table for an illustration. And, well, sometimes you find textbooks showing a La table, but making statements about the result of the Ln contraction that are only true in a Lu table (Greenwood and Earnshaw does this). So I am not sure if this should be weighted so highly: it does seem that outside the people who spend time arguing about it, this issue is not given much weight. But that's probably true of many specialised topics (e.g. is there d orbital participation in SF6?). And if that's the case, then if I read WP:CONTEXTMATTERS correctly we should focus on the subgroup of sources that actually do care and know about this. That page says Information provided in passing by an otherwise reliable source that is not related to the principal topics of the publication may not be reliable; editors should cite sources focused on the topic at hand where possible. In other words, I think that analysing group 3's composition, as opposed to just mentioning the elements there, should give sources more of a say here. Just like the precedent of how hypervalence clearly says that there isn't d involvement in these molecules like SF6 even though many textbooks will still tell you there is such a thing.
 * The "check and balance" that can prevent this from turning into a helium-in-group-2 situation (which is often advocated among the people looking at that issue, but no one listens to them) is IMHO simply to ask that a significant number of textbooks have agreed and followed this literature – which for Lu in group 3 is a "yes" even if it's not the majority yet, but for He in group 2 is an obvious "no" at this time.
 * I take the point that we shouldn't "add momentum" to such a change; we can only follow it. I agree with that. But it seems to me that among the people who analyse the situation the momentum has already led to the change, and I'd argue that those are the ones who matter most. Among people who care about the group 3 thing, Lu is for sure dominating. And among people who don't care about it, few seem to actually be protesting the change (like your response to S2).
 * Many of the sources are research articles indeed, but many are not. Well, among the Scerri pieces I linked, there's not only some research articles, but also a Chemistry World podcast, a general-interest book, an Education in Chemistry opinion piece, the Oxford University Press blog, and two popular books: The Periodic Table: A Very Short Introduction and The Periodic Table: Its Story and Its Significance. It seems to me that he's done a lot to bring this issue to the interest of general readers (I recently saw the last of those books in a general bookstore, after all). And in fact the advocacy also appears in such a popular book as John Emsley's Nature's Building Blocks (p. 651, 2011 edition), where he points to Jensen. So I'd argue that it's not only specialised sources that are behind this bandwagon. A general reader who just picks up some texts for laymen has actually a good chance of having heard about this issue now. Yes, that's mostly thanks to Scerri, but he's notable and his books have a wide reach.
 * Anyway, that's just my view. It's perfectly all right with me if you are not convinced to weight D3 as highly as I'd argue for; the discussion in this section is based on RS, and that's all I ask for.
 * Regarding "game changers". I just want to ask, what would you consider as a possible game changer? Say, what if in this decade:
 * IUPAC still doesn't make a decision, but La were to dip and Lu were to rise in popularity to the point where they are more or less equal?
 * What if La dipped significantly below Lu in popularity but IUPAC still had not made a decision?
 * What if IUPAC made a decision in favour of Lu, but the proportion of La vs Lu in textbooks remained the same as it is now?
 * And what if IUPAC made a decision in favour of La, but sources in spite of that massively migrated to the Lu form?
 * I just ask to clarify, of course. ^_^ Double sharp (talk) 16:33, 25 October 2020 (UTC)

IMO:

Sandbh (talk) 06:25, 29 October 2020 (UTC)
 * 1) We go through the same process we did with group 12 as TM or PTM.
 * 2) We go with Lu
 * 3) That's hard. It wouldn't necessarily tip the balance decisively in favour of Lu, but it's certainly a consideration, noting it can take a while for textbooks to catch up. It would also depend on the calibre of the Group 3 report, and the deliberations of the relevant IUPAC committed that result in their acceptance of the report.
 * 4) IUPAC is not necessarily authoritative, given their history of widely ignored recommendations, including some dumb ones scoffed at by Jensen.


 * I think a note about group 3 in the likes of what pl.wiki does will be in order if we don't mention the IUPAC taskforce in it.
 * My understanding is that a mention in a textbook is a context close enough because element textbooks are concerned with elements, and that WP:CONTEXTMATTERS merely advises against mentions that are not primarily about the topic at hand (in this case, chemical elements) whatsoever. Say, imagine a newspaper note about an airplane that has crashed into the IUPAC headquarters (is there such a thing as the IUPAC HQ?), and damaged was the room where the official group 3 was to be announced the next day, and the newspaper briefly mentions -La-Ac was the more popular form. I take it this is the kind of source one shouldn't use, but a chemistry textbook is fine.
 * I'm generally not a believer in game changers, but I'll find it acceptable (even though not preferable) if we decide to follow IUPAC no matter what. My preference would be that the IUPAC decision is used to tip the balance in an otherwise near-equal distribution (40:60) and not used as the decisive argument otherwise. I can't think of any other potential game changer.--R8R (talk) 11:54, 1 November 2020 (UTC)
 * I'm OK with not mentioning the IUPAC taskforce. As I've noted, I generally have no strong opinion about exactly what the note says. I feel that there should be one, but that is something I can be persuaded on.
 * Regarding WP:CONTEXTMATTERS; yes, for sure a textbook is more relevant than a source like the hypothetical one that you describe. However, is it the most relevant? I think that by the same token a source that specifically outright says it's going to focus on the group 3 issue in a section of it is going to be more relevant. A textbook is going to at least partially be concerned, after all, with pedagogy. It may simplify things to make it easier to learn, it may introduce its own nonstandard terminology to make things easier to learn, and it may even be forced to use some theories that are known to be wrong already just because the syllabus it has to follow has not been updated. So it comes back to my quibble about the whole hypervalence thing. If every serious source in the journal literature says there is no d involvement in SF6, but tons of textbooks still tell you that based on older ideas, then surely the fact that the literature is professing to refute that idea and their focus on it gives them more weight, no?
 * I mean, this is pretty much what's explained in WP:VNT: For example: George Washington was born in 1732. Let's consider a tour guide who says, "Washington D.C. is the capital of the United States, and it's named after George Washington (1722–1799), the first president ...", then that's just a mistake. But if we have an article written by some famed historian, stating something like "New historical evidence would date the birth of George Washington to 1722, ten years before it was usually known", then it would be a different thing ... regardless of whether such a hypothetical claim was true or not. And indeed, I know an example where something like that actually happened. Consider Johann Mayrhofer (Austrian poet): so many biographers say his birthday was 3 November, but new research (going back to his baptismal record) says it was 22 October, and we show that. Because the source saying 22 October specifically focused on his actual birthdate and provided historical evidence; for his other biographers, it is just one piece of information among many. That seems to me perfectly analogous to what's going on with the Lu vs La issue, except that the case seems even stronger: many textbooks say Lu is an f element, but quite a few are starting to disagree, and the vast majority of the sources that specifically focus on Lu vs La say that Lu is a d element that belongs in group 3 and provide evidence for it. And just like a source focusing on Mayrhofer's birthdate specifically is more reliable than one who is writing a biography of him and therefore has to treat it as just one among many pieces of information that may not have been analysed – a source focusing on the group 3 issue specifically is surely more reliable than one who is writing a whole textbook covering the chemistry of all the elements, for which La and Lu are just two among over a hundred. So it would be like the Mayrhofer thing, except that we'd have a situation where some biographers start to give him the right birthday, which seems to make the case for a change even stronger.
 * So it's my viewpoint that the most relevant sources are the tons focusing on the issue and saying that Lu should be in group 3. Okay, yes, there are a few dissenters. That's why we can have a footnote: the situation in the most relevant sources is not quite settled but very clearly skewing strongly to Lu. In the next tier of sources, we have the usual lag of textbooks when it comes to this information, but some have already followed. Double sharp (talk) 12:33, 1 November 2020 (UTC)
 * My understanding that the difference between the Mayrhofer example and the group 3 issue is that the statement "Mayrhofer was born on October 22" is a matter of fact; it can be either true or false. Same with "SF6 uses d-orbitals": it can be demonstrably true or false. In contrast, "lutetium is a group 3 element" is not; whether this statement is agreed upon or against, it's a convention one way or another. The true-or-false statement here would be, "for each professional secondary source that suggests that group 3 is Sc-Y-Lu-Lr, there are at least two that say it's Sc-Y-La-Ac." Or you can try to come up with a different statement that is either true or false, but it should be clear there is a difference between the Mayrhofer and SF6 examples on one hand, and the group 3 example on the other.--R8R (talk) 13:14, 1 November 2020 (UTC)
 * Ah, I think we've now gotten to the point where we currently disagree. Is "lutetium is a group 3 element" a convention, or is it a true-or-false statement? I think that, once you define what a "group 3 element" is, then it immediately becomes a statement that you say is true or false, no? And the same thing for statements like "lutetium is a transition metal" or "lutetium is a d block element", all of which amount to the same thing. Once you define the group 3 elements / transition metals / d block elements by properties, independently of the elements, then "lutetium is a group 3 element" becomes not just a convention but something you can prove or disprove according to your definition.
 * More importantly, it seems to me that the sources in question are treating it as a true-or-false statement. I mean, look at some of the sources: they seem to be pretty clear about what they're saying. Merz and Ulmer says "only lutetium, but not lanthanum, may be considered as a transition metal." Tsimmerman says "This should disqualify them [Lu and Lr] from holding terminal positions in f-block". Fang et al. says "lutetium should occupy the position normally given to lanthanum in the periodic table." And Jensen says "Since such an interpretation is not possible for Lu/Lr, it pretty much determines that this pair should be assigned to the d-block whereas the La/Ac pair should be assigned to the beginning of the f-block." All of these authors seem to be presupposing the idea that there is a sense of correctness and wrongness when it comes to placing elements on the periodic table, because they give criteria that "determines", "disqualifies" placements, to argue why some element "should" occupy this position and not that other one, to argue that we "may" or may not consider something as a transition metal. And it seems that apart from Sandbh who thinks that other forms will continue to have their uses in their contexts, La-Ac supporters seem to have the same idea. Lavelle says "Please leave lanthanum (La) and actinium (Ac) where they belong, in the d-block." That shows the idea that there is some correctness, of places where elements "belong" on the PT. And Restrepo said "therefore La must be the element located at the beginning of the third row of transition metals", with a "must".
 * So it seems that whether they support La or support Lu, the idea in general among the scientists who care about this is that "lutetium is a group 3 element" is a true-or-false statement, not only a convention. The disagreement is just on whether it is true or not. So that's why I think the situation is more like the Mayrhofer and SF6 ones. But what do you think of this argument? Double sharp (talk) 14:25, 1 November 2020 (UTC)
 * I understand what you mean, but it appears to me there is something you're missing here. Each individual scientist may think they have the definition of a block, and that's fine. The thing is, it is not necessarily the case that they all think of the same definition, and that's where the problem lies. You may recall Scerri as the chairman of the IUPAC group 3 taskforce also sought to use the definition of a block, but he couldn't come up with it. This is a very good sign the problem is not at all that easy. That's where conventions come in: people have to agree to use the same definition of what a block is, and if that were feasible, that definition would've likely already appeared and been recognized as such. (Lavelle and Scerri think differently on the same issue; does that really seem like this is not where conventions should come in?) In contrast to that, there is not going to be a misunderstanding about the meaning of the statement "Mayrhofer was born," and there is no sense that the meaning of that statement was ever agreed upon rather than arose naturally.--R8R (talk) 12:00, 4 November 2020 (UTC)
 * I see what you mean too, but isn't that just about the arguments they use? Yes, some people argue on block-based grounds, and they have different ideas of a block in mind. But the statement at hand is not "what is a block", it's "is Lu a group 3 element". The meaning of the statement "Lu is a group 3 element and La is not" is clear, it means "Lu and not La belongs in the same column of the periodic table as Sc and Y". I'd think from those quotes I gave that if you asked a bunch of La and Lu supporters about that statement, they would agree what it meant, and they would agree that it was either true or false. (Of course they wouldn't agree on which of it it is, but there would be agreement that it is a fundamentally decidable proposition.) It's the way you get there where the individual conventions live, like "what is a block", like "what criteria should be used to decide PT placement"; but those are just justifications, and don't impact the clarity of the statement at hand and its nature as something that can be either proved or disproved. Obviously, if scientists find themselves at different conclusions, they must be justifying their conclusions in different ways. In fact, some scientists who find themselves at the same conclusion are justifying it in different ways (Jensen vs Scerri, for example). So people disagree on how they get there, people disagree on what the truth of a statement is, but they agree that it is either true or false. That does not seem different from any other disagreement to me, honestly. And that's why I feel it should be treated the same way: authors differ in methodologies, but they agree the statement at hand is either true or false, and a strong majority says it's true. So we reflect that and just say that there's some opposition, giving it its due weight. Or maybe I misunderstood you? Double sharp (talk) 12:22, 4 November 2020 (UTC)
 * Hmm. I think you effectively said the opposite not too long ago? "But the statement at hand is not "what is a block", it's "is Lu a group 3 element" is nice, but I take it it contradicts the notion of "Is "lutetium is a group 3 element" a convention, or is it a true-or-false statement? [...] And the same thing for statements like "lutetium is a transition metal" or "lutetium is a d block element", all of which amount to the same thing." So is it the same or is it not?
 * "The meaning of the statement "Lu is a group 3 element and La is not" is clear, it means "Lu and not La belongs in the same column of the periodic table as Sc and Y" -- I take it the two statements mean precisely the same. There is no explanation added by any of these statements to the other as far as I can see. I also take it there is no controversy about the statement "a group 3 element is a d-block element." This means if Lu is a d-block element, it's also a group 3 element (because nobody suggests a different position in the d-block for Lu), and if it's a group 3 element, it's also a d-block element. The same goes for La.
 * However, let's summarize it this way. What is exactly a group 3 element? What's the definition that's clear to everyone and that's going to unambiguously answer that question? If there were such an ultimate definition, then it is without a doubt that a vast majority of reliable source would accept it and what results it produced, right? Well, there is no such definition and there are no such results, which means there is no ultimate answer (but there is an answer to the question "what does it mean when we say a person is born?"). Being in the same column is not an answer; it's the same statement but in different words. The answer could be about electronic configurations, but Scerri rejects such an answer. It's not that easy to give a straightforward answer, which is where conventions come in.--R8R (talk) 13:07, 4 November 2020 (UTC)
 * Well, maybe I'm not explaining myself perfectly well. ^_^ I agree "lutetium is a group 3 element" = "lutetium is a transition metal" = "lutetium is a d block element" as statements, because they lead to exactly the same picture in terms of the PT, like you say in the second paragraph: the one I've been advocating we change back to with Sc and Y over Lu. What I don't think is the same is the question "what is a block". No, there isn't such a thing as the definition that's clear to everyone of what brings an element to the d block, but that's not exactly the statement at play. Because there's general agreement that there is such a thing as a correct placement of elements in the PT; what's not agreed is how to get at it. Even with blocks, there's a general total agreement on exactly how many they are, what they're called, and apart from the group 3 dispute even exactly which elements go in which, after all. So I'd say that the analogue to the question "what does it mean when we say a person is born" here is "what does it mean when we say some element belongs somewhere in the PT". Yes, there's no formal definition, but does it matter that much when apart from group 3 everyone seems to know what elements go in what block anyway?
 * And, the analogue to the questions like "what is a group 3 element" or "what is a block", which are rather really more like "what criteria put an element in group 3" or "what criteria put an element in the d block" (because "group 3" and "block" seem to be de facto understood even if no formal definitions are agreed on), are rather things about how to find out the information about when someone was born: the birth certificate if it survives, maybe earlier the historical records, maybe the baptismal list, recollections of relatives interviewed afterwards, and so on. Both are about what things should be used to decide a question that is widely understood. (It's not an exact analogy obviously because the real world is more complicated. If you prefer, I can go for a more chemical analogy to be more exact, but it'd be less colourful. ^_^) Historians can debate on which of these sources are more reliable for determining a person's date of birth, but they agree that there's in principle a right answer even if in some cases maybe we can't find it out. Likewise, chemists can debate on exactly what criteria are the most reliable for determining where an element belongs in the periodic table, but by and large they seem to agree that there's in principle a right place for it. So I think the right question is "where is Lu correctly placed in the periodic table = is Lu in the group with Sc and Y = is Lu a group 3 element = is Lu a d block element = is Lu a transition metal", and the definitions are more akin to the debate about how to find out that correct placement. In other words, the question to be answered is "where does Lu belong in the periodic table", and that is not subjective and not subject to convention and is clearly understood; what is debated is "what definitions and criteria are relevant to decide on where Lu belongs in the periodic table", but that's a secondary-level thing. So something like this:


 * Well, what do you think? Double sharp (talk) 15:18, 4 November 2020 (UTC)


 * I agree that "lutetium is a d block element" is not the same as "what is a block." No question about it. However, it seems to me it is rather obvious that you need to answer the latter question before you can formally agree or disagree with the former. (Even in the famous statement "I think, therefore I am," you need to understand what, for example, the words "think" and "am" mean before you can informedly agree or disagree with it. "You were clearly not thinking when you said that" -- does it mean that the person didn't exist at that moment, too, or that the original statement is therefore wrong? Or are there nuances?)
 * "there's general agreement that there is such a thing as a correct placement of elements in the PT" -- I don't think that's the case. For example, Scerri suggested a table in which Lr is located under La, and after providing his rationale he said that there was no universal PT, and that the elements are not necessarily tied to a rectangular grid in the likes of our PT. Sandbh has also said something like this a number of times this year, too, and I agree with him.
 * The difference is that birth is a real thing, or at least my common sense is that it's common to treat it as such. In contrast, the periodic table pictures relationships between elements, emphasizing some over others, and relationships are not a real thing pretty much however you look at it, that's something we like to think of. If you look at it this way, I hope it will be easier to see why your analogy does not seem convincing to me. In both cases, the second question is of the nature that resembles "upon the basis of what convention do we agree Lu should be in this place in the PT/the person is registered as born?" Both of these questions represent conventions. One could, of course, reduce any word to a convention that it means something, but it's useful to take something for granted. And birth seems like a very basic thing and people more or less agree it's a thing, not a convention. I'd say that suggesting the same treatment for emphasizing some relationships between elements (an entirely nade-up concept to begin with) over others as a thing and not a convention is a bit too much. Scerri doesn't do this. A Soviet source I've read refers to such a thing as "blurring of periodicity" with respect to the 5d and 6d positions in the PT. I propose that we shouldn't claim there is an ultimate answer, either.--R8R (talk) 14:28, 8 November 2020 (UTC)
 * Well, your last paragraph is where I disagree. People are treating this as a thing, rather than as a convention. They must be, or else they wouldn't use the language they do. As shown from my quotes: they say something determines the placement, that something must be put here, that a form is a mistake, that a form must die, that a placement is disqualified, that one may not classify an element this way. Such rhetoric presupposes a mode of thinking that this is not a convention but a thing. Since that is how most sources talk, in my opinion we have to follow it. That's just because of the RS situation. Scerri did not suggest a La-Lr table (that was Poliakoff AFAIK), and in fact he not too long ago did indeed say there was such a thing as an optimal PT. The sources may argue about how you get to the conclusion that some PT is better, and which one it is. But that one is better when it comes to the group 3 problem, they don't argue. Double sharp (talk) 14:42, 8 November 2020 (UTC)
 * I'd say that the context, in which those phrases were said, helps establish that these phrases do not imply there is the one ultimate way. For example, in the article in which Scerri says that -La-Ac "must die," he also says, "There is a different reason why placing lutetium and lawrencium, rather than lanthanum and actinium, in group 3 is the better option" (emphasis added), so I would not overestimate the importance of those out-of-context phrases. But if you don't see it that way, I guess it's best to accept that we differ on that. But just to be clear, "optimal" is not "right" or "ultimate," and something can only be optimal if you agree for what it should be optimal, explicitly or implicitly (and that's where conventions come in).--R8R (talk) 15:16, 8 November 2020 (UTC)
 * Yes, I think we can accept that we differ on it. All in all, I want to thank you very much for your opposition. Even though I disagree, I can see your case. ^_^ Double sharp (talk) 01:00, 12 November 2020 (UTC)

Was that ping for me or R8R?? Sandbh (talk) 05:10, 9 November 2020 (UTC)
 * Sorry, it was a typo on my part and meant for User:R8R. Double sharp (talk) 10:31, 9 November 2020 (UTC)

Other discussion
I'd like to read your article about the group 3 issue. The images linked by User:Double sharp (thank you!) are too low quality to enable a translation into English. Is there anything that could be done about this? Sandbh (talk) 21:29, 19 October 2020 (UTC)


 * There is no fundamental requirement for any element to appear only once on the PT. An appreciable number of periodic tables do not observe this "non-requirement". Sandbh (talk) 22:50, 20 October 2020 (UTC)

Introduction
As promised, here is a discussion on the (non-)relevance of aesthetics and regularity in the context of the Group 3 question. It is taken and adapted from my peer-reviewed open access article which now has 400 accesses, in Foundations of Chemistry. The editor is Eric Scerri, who is also the chair of the IUAPC Group 3 project.


 * I caution readers to not confuse Eric's personal view on the group 3 question with his role as the editor of FoC, nor with his role as the chair of the IUPAC project.

My conclusion is that, akin to a game of whack-a-mole, attempts to improve regularity in the appearance of the periodic table increases the number of irregularities amongst various other properties and relationships across the table, and cognitive dissonance with respect to chemical relationships between or within groups or series of elements. Further, while Nature does not care about aesthetics, the composition of Group 3 as Sc–Y–La–Ac appears to be more consistent with the texture of the world.

Scerri sets the scene
Scerri (2008, p. 57) has argued for lutetium under yttrium (and helium over beryllium), since the periodic table can then be arranged, from a philosophical point of view, so that it shows the greatest degree of regularity and symmetry. Such a table may better reflect the regularity of the periodic law. He cites as an example, the left-step or Janet periodic table (Fig. 9). Such a table facilitates a regular array of vertical triads (Fig. 10), in which the middle element of the triad has an atomic number that is the average of those of the first and third elements. Scerri does not support lanthanum under yttrium since, in a 32-column table, and on the basis of regularity and symmetry, this once again results in awkward split d-block (Fig. 11).[n13]
 * n13: Hamilton (1965) shows a periodic table extract (Groups 1 to 11, plus footnoted lanthanoids and actinoids, showing Ce, Pr…Lu; and Th, Pa…Lw) with a split d-block (the gap is between Groups 3 and 4) and says that—without any fuss—this is “the periodic table as it is usually presented”. Reger et al. (2010, p. 295) write that “perhaps” the correct shape of the 32-column periodic table should feature a split d-block given the electron configurations of La and Ac, but that “we avoid these structures by splitting the f-block from the rest of the periodic table. This also has the advantage of being able to print a legible periodic table on a single piece of paper.” (They show La below Y in the rest of their book.)


 * In a similar vein, Scerri (2020b, p. 5) notes that with respect to the 32-column form, “After any new insights are gained, one can well return to the 18-column format with deepened knowledge.”


 * The split-d table dates from as early as 1934 (Romanoff). It was the table of choice for van Spronsen (1969) in his history of the first hundred years of the periodic system of chemical elements.

Scerri's argument remains inconclusive
His argument remains inconclusive as there is no basis to regard regularity or symmetry as fundamental requirements (Scerri 2004, p. 149; 2019, p. 385). Stewart (2018b, p. 75) observed that, “Triads are a consequence of the structure of the system and cannot at the same time be its cause.” Scerri (2020a, pp. 387, 401) acknowledges that we should be aware of arguments based on regularity or symmetry. Jensen (2019), whose 1982 article in the Journal of Chemical Education kicked off the debate on the composition of Group 3, recently attacked the relevance of [vertical] triads.

Curiously, as discussed later in this article, increasing regularity in the shape of the periodic table increases the number of irregularities amongst various other properties and relationships across the table.[n14] Indeed, as Imyanitov (2016, pp. 153–154) observed: If one seeks for the maximum chemical utility…[one] should opt for the more ‘unruly’ tables. If one seeks maximum elegance and orderliness above all…[one] should favor the more regular representations.
 * n14: A simple example is to rearrange the line of elements shown on the cover of Bent’s (2006) monograph, into the conventional 18-column layout with the two Group 3 options, as follows:


 * [here]. ￼

The historical obsession with symmetry
The obsession of the Greeks with the concept of symmetry retarded progress in astronomy for at least 1500 years (Yang 1996, p. 271). They perpetuated the idea of the Harmony of the Spheres and the Dogma of the Circles. According to these works, the heavenly bodies must observe the most symmetrical rules, and the circle and the sphere are the most symmetrical forms. But the heavenly bodies do not make simple circular motions. So they tried to fit their motions with circular ones superposed on circular ones. When that did not work either, they tried circular ones on circular ones on circular ones, and so on.

My shock and realisation
The first time I saw a 32-column table with a split d-block (Fig. 11) I thought it must have been “wrong” since it appeared so awkward; I later came to realise that I’d subconsciously adopted the Western cultural obsession with symmetry.[n15] Jensen earlier referred to the abuse of (Platonic) symmetry considerations in the construction and interpretation of periodic tables in general, including to the extent of triumphing over the inconvenient facts of chemistry (Jensen 1986, passim; 2003, pp. 953–954).


 * n15: In a related manner, notions of beauty and ugliness show some variation across time, and between cultures and people (Shiraev and Levy 2013, p. 102). For example:


 * Mountains are seen as sublime expressions of nature; only two hundred years ago they were regarded as loathsome things to be avoided at all costs (Bayley 2015).


 * Two years before it was finished, the great Paris “intellos” of the day lined up in opposition to the Eiffel Tower, writing letters to the papers denouncing it as an ugly and hateful column of bolted tin; of course, it is now one of the world’s most beloved monuments (Bayley 2015).


 * Foreigners in Japan were known to refer to a good deal of ikebana (flower arrangement) as unattractive (Shiraev and Levy 2013, p. 102).


 * The ACS Division of Inorganic Chemistry had been using a split-d table as its e-mail header, without any concerns being raised, as far as I know, on ugliness or disorderliness. It looks engaging to my subjective eye—ordered, yet with intriguing flourishes:


 * [here]


 * Scerri (2020b, p. 11) reports that the logo was withdrawn due to the controversy associated with the Group 3 question. It has subsequently been reinstated.

Symmetry breaking
An emerging field of thought is the importance of symmetry breaking,[n16] rather than pure symmetry:


 * …symmetries matter, largely because we like to see them broken sometimes: the laws, particles and forces of physics all have their roots in symmetry-breaking. They create what David Gross of the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara, calls the “texture of the world”. These considerations have led Florian Goertz at the Max Planck Institute for Particle and Astroparticle Physics in Heidelberg to propose the existence of a new particle that is single-handedly capable of cleaning up five of the stickiest problems in physics. “Complete symmetry is boring,” says Goertz. “If symmetry is slightly broken, interesting things can happen.” (Brooks 2018, p. 30)[n17]


 * n16: Yang (1996), p. 286:
 * "Through the work of many physicists, the concept of broken symmetry was introduced into elementary particle physics in the 1960s and 1970s. The idea was, in the simplest language, to keep the mathematical forms symmetrical, but the physical consequence unsymmetrical. The standard model, for which Glashow, Salam, and Weinberg shared the Nobel prize in 1979, was based on gauge theory with broken symmetry. It has been extremely successful."


 * n17: "Physical chemistry is fundamentally asymmetric. How could it not be when the proton weighs so much more than the electron?" (Philip Stewart, pers. comm. 30 Dec 2019). A recent article along these lines appeared in New Scientist:


 * "Evidence of new physics could have been under our noses all along
 * Many of these remaining problems boil down to one. Crudely phrased, some things are exceptionally small while related things are exceptionally big. This is known as the hierarchy problem, and once you spot it, you start seeing it everywhere.


 * Take the four fundamental forces of nature. The weakest two are gravity, and the weak nuclear force, which only operates on the tiniest of scales and is responsible for certain types of radioactive decay. The weak force is weak, but compared with it, gravity is some 25 orders of magnitude weaker—a bizarre state of affairs that, as yet, has no good explanation.


 * The asymmetry reappears elsewhere. Dark energy, the mysterious force that is causing the universe’s expansion to accelerate, is 120 orders of magnitude weaker than we would expect. Dark matter, which is the dominant form of matter in the universe, interacts very weakly with regular matter. Neutrinos, the lightest particles in the standard model, are thousands of times lighter than anything else.


 * These disparities are profoundly vexing to physicists, who prefer to see related parameters in a theory take broadly consistent values. This preference for "naturalness" drives much theoretical speculation—some would say to a fault. 'Nature doesn't care about our aesthetics,' says [Nathaniel] Craig [a theoretical physicist at the University of California, Santa Barbara].

* * *


 * Ten years on, nothing has changed. We were fixated on supersymmetry for too long, says Isabel Garcia at the University of California, Santa Barbara, searching under the convenient street light to the detriment of the field. But the story of the LHC is far from over. The collider has recorded only 3% of the data we expect it to collect in its lifetime, and an upgrade to higher energies in 2020 will further raise its chances of seeing something surprising.


 * But the LHC's failure to break any new ground has emboldened a new generation to question the hunches that motivated previous searches. 'This optimism is most widespread amongst the youth,' says Matthew McCullough, a theoretical physicist at CERN. 'We’ve shaken off the cobwebs of the theories handed down by our PhD advisers.'" (Eure 2019)


 * It remains to be seen if the YAPs (young asymmetrical pups) can teach the OSDs (old symmetrical dogs) some new tricks.

As Eugen Schwarz (2019, pers. comm., 8 Dec) stated, "The real, rich pattern of elements’ chemistry does not fit into a clear-cut rectangular grid." This view is consistent with that of Dias (2004, p. 375), who asserted that:


 * "A periodic table is defined as a partially ordered [italics added] set forming a two-dimensional array which complies with the triad principle where any central element has some metric property that is the arithmetic mean of two flanking [i.e. horizontal] member elements."[n18,n19]


 * 18: Klein (1995, pp. 341–342) elaborates the concept of a periodic table as a partially ordered set:
 * Even in elementary chemistry texts many "rules of thumb" are given which in effect make partial orderings of various chemico-physical properties (melting points, boiling points, electronegativities, solubilities, reactivities, etc.). For example, the ionization potentials of elements arranged in a suitable typical periodic chart generally decrease in proceeding down columns and in proceeding right-to-left across rows, so that while some pairs of elements have ionization potentials ordered by this rule, others pairs don't…Indeed, the periodic chart can be viewed as what we might call a multi-poset, where there are ordering links along both vertical and horizontal directions but orderings are to be in different directions (interchanging upward vs. downward and/or leftward vs. rightward) for various properties.


 * 19: Even so I consider that (a) asymmetry cannot be appreciated or understood without understanding (b) symmetry, and how and why things go from (b) to (a). See also Hegstrom and Kondepudi (1990), and Rosen (1996).

Real chemists
In this vein, Mendeleev used horizontal triads when he predicted the properties of the then undiscovered elements scandium, gallium, and germanium. He discussed his technique using the horizontal triad arsenic-selenium-bromine to estimate the atomic weight of selenium (Scerri 2008, pp. 585–589).

A high degree of orderliness, and explanatory power, can nevertheless be found in Rossotti’s (1998) split d-block periodic table template (Fig. 12).

Rossotti shows where each subshell starts; how the lanthanoids and actinoids are interpositioned between Groups 2 and 4 and, in this instance, the electron configuration make-up of gadolinium and its predecessor, europium. Here, the lanthanoids run from cerium to lutetium; and the actinoids from thorium to lawrencium.

The split d-block is thus integrated into the overall design of the table.

The domain of chemistry
A related consideration is that the internal structure and external shape of a chemical periodic table is determined by chemical facts rather than considerations of regularity, beauty or symmetry (Cao et al. 2019, p. 26, passim). Here, the use of multiple considerations to triangulate a solution is consistent with the role of classification science, as well as the premise that “Classes are usually defined by more than two attributes…” (Jones 2010, p. 169). In other words, in the absence of a categorical solution we are obliged to use quantitative or qualitative arguments to establish a solution.[n24]


 * 24: Jones adds (2010, pp. 169–171):
 * "Though classification is an essential feature of all branches of science, there are always hard cases at the boundaries. The boundary of a class is rarely sharp…Scientists should not lose sleep over the hard cases. As long as a classification system is beneficial to economy of description, to structuring knowledge and to our understanding, and hard cases constitute a small minority, then keep it. If the system becomes less than useful, then scrap it and replace it with a system based on different shared characteristics."

Conclusion
It is ironic that, akin to a game of whack-a-mole, attempts to improve regularity in the appearance of the periodic table increases the number of irregularities amongst various other properties and relationships across the table, and cognitive dissonance with respect to chemical relationships between or within groups or series of elements. While Nature does not care about aesthetics, the composition of Group 3 as Sc–Y–La–Ac appears to be more consistent with the texture of the world.

That said, since periodic tables or systems form a continuum-like series of representations, different approaches to the Group 3 question (even that used within the IUAPC) will continue to have their uses. And please remember to explain the relevant context to your students. --- Sandbh (talk) 05:21, 25 October 2020 (UTC)

Closure
I would like to propose that this thread be closed with no action. We have since heard from Sandbh that Scerri is writing an article for Chemistry International which will contain some information about how the IUPAC project is going. Since things are happening on schedule there, it seems to me that it doesn't make sense to pursue this line further when the doings of that project are going to be of utmost importance when it comes to affecting the situation one way or the other. We may revisit it once that article is published.

The thread can then be archived with the understanding that we'll not re-broach this topic till then. It simply records our current positions and rationales with no prejudice at all to changing them when new information arrives in the form of news from the IUPAC project. So, we will have a friendly understanding (I hope) that say, I lean Lu and Sandbh leans La, but we will not discuss it again until something really new happens off WP on it. Double sharp (talk) 20:50, 13 November 2020 (UTC)