Wikipedia:Featured article candidates/Thorium/archive1


 * The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article candidates. No further edits should be made to this page.

The article was promoted by Sarastro1 via FACBot (talk) 22:22, 19 January 2018.

Thorium

 * Nominator(s): Double sharp (talk), R8R Gtrs (talk) 14:56, 17 December 2017 (UTC)

The unsung natural radioactive metal (uranium gets all the press). I rewrote this article and sent it to GA in September 2014, having been motivated by the since semi-retired Mav's 2010 statement that he wanted to send it to FA. Since June 2016, R8R and I have been doing extensive work on it (including a PR; we addressed some of his concerns together even after the PR have been closed). This element deserves to be saved from the development hell its article has been going through and I hope your comments here will finally rescue it! (P.S. I recently helped at the PR for Smerus' project of Felix Mendelssohn, and some of the language in my nomination statement is inspired by his. ^_^) Double sharp (talk) 14:56, 17 December 2017 (UTC)

Image review

 * Suggest scaling up the decay chain image
 * Good idea. Done.--R8R (talk) 20:12, 17 December 2017 (UTC)


 * File:Thorium_sample_0.1g.jpg: confused by the licensing here - it has an NC-ND tag, which is not permitted on Commons, but also a Free Art tag?
 * The author pointed me at Licensing and Multi-licensing. I think that makes it clear.--R8R (talk) 20:12, 17 December 2017 (UTC)


 * File:Uranocene-3D-balls.png is tagged as lacking a description
 * Added description.--R8R (talk) 20:12, 17 December 2017 (UTC)


 * File:Jöns_Jacob_Berzelius.jpg: source links are dead, needs a US PD tag. Nikkimaria (talk) 16:35, 17 December 2017 (UTC)
 * Used a different file instead.--R8R (talk) 20:12, 17 December 2017 (UTC)

Biological

 * Is leached used correctly here? Leached into strikes me as an unusual usage. &middot; &middot; &middot; Peter (Southwood) (talk): 14:35, 18 December 2017 (UTC)
 * Well spotted, thank you. Reworded the sentence to match information in the source a little more closely.--R8R (talk) 16:24, 18 December 2017 (UTC)

Comments Support by XOR'easter

 * In the "isotopes" section, it says, "232Th is the only isotope of thorium occurring in quantity in nature, and thorium is usually considered to be a mononuclidic element." But then, a little later, "The International Union of Pure and Applied Chemistry (IUPAC) reclassified thorium as a binuclidic element in 2013" (ten years after the reference used to support the "usually considered mononuclidic" claim). A little clarification on what the status quo is &mdash; rather than making a claim and then walking it back &mdash; would help.
 * I'll give this a second check: when I wrote this in 2014, it was true that IUPAC's reclassification wasn't really followed very much, but now that 2018 is almost upon us things may be different. Double sharp (talk) 09:28, 22 December 2017 (UTC)
 * It does seem that Th is usually considered a binuclidic now, so I've reorganised this, removing the claim about it usually being considered a mononuclidic element. Now the second sentence you mention reads "The International Union of Pure and Applied Chemistry (IUPAC) reclassified thorium as a binuclidic element in 2013; it had formerly been considered a mononuclidic element." Double sharp (talk) 15:55, 13 January 2018 (UTC)
 * References 5, 28, 29, 63, 77, 83, 101, 115, 128, 134, 135 and 145 are showing the "Check |url= value" warning message.
 * It looks like this has been addressed already. Double sharp (talk) 16:01, 13 January 2018 (UTC)
 * Reference 23 points to The Feynman Lectures on Physics, and it would be nice to have the title wiki-linked. Also, the referenced chapter can be read online. XOR&#39;easter (talk) 20:09, 21 December 2017 (UTC)
 * The links have since been added. Double sharp (talk) 15:57, 13 January 2018 (UTC)
 * Actually, no: you can't have both an internal link in the title and an external link (because that should also appear in the title), and it throws up an error. I think the fulltext is more important, so I've decided in favour of the external link. Double sharp (talk) 15:59, 13 January 2018 (UTC)
 * I must be able to fix the referencing problems in a week. Sorry for the delay.--R8R (talk) 14:13, 23 December 2017 (UTC)

I think we've addressed all your comments. Double sharp (talk) 16:01, 13 January 2018 (UTC)
 * I agree. Thank you! XOR&#39;easter (talk) 02:15, 14 January 2018 (UTC)
 * I saw a few "clarification needed" tags, so I rephrased a couple sentences, hopefully without garbling the intended meaning. With that addressed, and not seeing any other problems, I am in support. XOR&#39;easter (talk) 18:47, 14 January 2018 (UTC)

Sources review

 * The citations with links to google books all carry red error messages. I haven't investigated, but they need to be looked at.
 * (All Google Books links have been removed, as stated below.) Double sharp (talk) 15:53, 13 January 2018 (UTC)
 * Ref 51 (Persson): returns "page not found"
 * IUPAC appears to have restructured its website, and this paper is now on De Gruyter's website (the publisher's) and is hidden behind a paywall; thus I have removed the link. Double sharp (talk) 15:53, 13 January 2018 (UTC)
 * Ref 107: What makes straightdope.com a reliable source?
 * It isn't. I've removed it; some of its information could be substantiated by other sources and I have replaced them, while I could not find the rest and have removed it. Double sharp (talk) 15:43, 13 January 2018 (UTC)
 * Ref 120: Check publisher. I can't see any mention of Battelle Memorial Institute: the publisher appears to be SciTech Connect
 * The front page of the document (click "View Full Text" to see it) reads "Released 1994 / Prepared for the U.S. Department of Energy under Contract DE-AC06-76RLO 1830 / Pacific Northwest Laboratory / Operated for the U.S. Department of Energy / by Battelle Memorial Institute". Does this not make Battelle Memorial Institute the publisher? SciTech Connect cannot possibly be the publisher, as it was launched in 2013, nineteen years after this paper was released. Double sharp (talk) 15:49, 13 January 2018 (UTC)
 * Ref 146: The Guardian should be italicised
 * ✅ Double sharp (talk) 15:45, 13 January 2018 (UTC)
 * Ref 148: Requires retrieval date.
 * ✅ Double sharp (talk) 15:46, 13 January 2018 (UTC)

Other than the above, the sources look in good order and of appropriate quality and reliability. Brianboulton (talk) 20:51, 21 December 2017 (UTC)


 * I'll fix the above in a week unless Double sharp manages to do it before the week passes. Sorry for the delay.--R8R (talk) 14:11, 23 December 2017 (UTC)
 * FWIW, I never link to Google books in my FAs (unless the source is out of copyright) because the links vary with location and over time. Basically, they aren't sufficiently stable to be useful. Jimfbleak - talk to me?  07:55, 28 December 2017 (UTC)
 * I've removed all the Google Books links. Double sharp (talk) 15:10, 7 January 2018 (UTC)

I think I've addressed all your concerns except the middle one, for which I've given an explanation why I think Battelle Memorial Institute is probably the correct publisher (I could be misreading this). Double sharp (talk) 15:53, 13 January 2018 (UTC)
 * Fair enough. Brianboulton (talk) 16:10, 13 January 2018 (UTC)

Comments Edwininlondon
I have no expertise in the field, but I can offer a few comments on prose:

More later. Edwininlondon (talk) 15:58, 23 December 2017 (UTC)
 * I find the first sentence a little low on info. Would it not be better to open with something like "Thorium is a weakly radioactive chemical element ...?
 * A while ago DePiep was rephrasing all the first sentences of the chemical element articles (e.g. Ac) so that they all read "X is a chemical element with symbol Y and atomic number Z". I don't think this was a terribly good change precisely for this reason, so I've changed it back. Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * only two radioactive elements that still occur naturally -> in the universe or on earth?
 * Both, so I've changed it to "in the universe" (since the earth is evidently in there ^_^). Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * The number of f electrons increases -> I assume you're still talking about going from thorium to plutonium
 * Yes; I've merged the two sentences to try to clarify this. Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * in which +4 is also the highest possible state, but +3 also -> also twice
 * Removed the second "also". Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * Like many of the early and middle actinides (up to americium, and also expected for curium), thorium forms the yellow cyclooctatetraenide complex Th(C8H8)2, thorocene -> strictly speaking the actinides form something like thorocene but not actually thorocene
 * Changed to "Like many of the early and middle actinides (up to americium, and also expected for curium), thorium forms a cyclooctatetraenide complex: the yellow Th(C8H8)2, thorocene." Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * 5 pm) they behave -> comma before they?
 * Added. Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * only by the r-pr. -> Twice only
 * I've tried to address this one, though I must confess that I'm not quite happy with the wording here still, so further suggestions would be welcome. ^_^ Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * involve thorium isotopes: uranium–thorium dating, involving -> involve twice
 * Changed the second "involving" to "based on". Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * also the highest possible state, but +3 also -> twice also
 * I think we've addressed this one already. Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * In acidic aqueous solution -> should that not be In an acidic?
 * I've changed it. Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * Because of the abrupt loss ... uranium, because -> twice because
 * Removed the second "because" and changed the comma to a semicolon. Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * On Earth, thorium is not a rare element -> feels repetitive, mentioned 2 paragraphs earlier
 * Changed to "Thorium has a crustal abundance comparable to that of lead and molybdenum, twice that of arsenic, and three times that of tin. It nevertheless only occurs as a minor constituent of most minerals, and was for this reason previously thought to be rare." Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * moved cerium and thorium to ... cerium, and thorium.  -> Twice
 * Changed to "...Mendeleev moved cerium and thorium to group IV in 1871, which also contained the modern carbon group (group 14) and titanium group (group 4), because their maximum oxidation state was +4." Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * twentieth century -> inconsistent with 21st
 * Changed to "20th". Double sharp (talk) 05:57, 24 December 2017 (UTC)
 * Exposure is raised for people who live near thorium deposits, radioactive waste disposal sites, -> deposits or radioactive
 * ✅ Double sharp (talk) 15:53, 28 December 2017 (UTC)
 * Wickleder, M. S.; Fourest, B.; Dorhout, P. K. (2006) probably needs an ISBN
 * Yes, added.--R8R (talk) 17:54, 29 December 2017 (UTC)


 * Emsley, John (2001) has an ISBN 10 instead of 13
 * Fixed.--R8R (talk) 17:54, 29 December 2017 (UTC)
 * This somehow didn't save the last time; it has now.--R8R (talk) 12:45, 30 December 2017 (UTC)


 * I get a Check |url= value warning for refs 5, 28, 29, 63, 77, 83, 101, 115, 128, 134, 135, 145
 * Some user at one moment all of a sudden changed some regularly formatted templates linking to Google Books so that they included google books. I didn't see what was good in that change but since I didn't see at the time what was bad, either, I left it as it is. Will have to fix now, though. --R8R (talk) 17:54, 29 December 2017 (UTC)
 * Done.--R8R (talk) 12:45, 30 December 2017 (UTC)


 * Quite a few notes seem to be missing a source, a d f j
 * At the moment, only two have no sources: a and f. Do you really see the info in either note as WP:likely to be challenged? I rather don't.--R8R (talk) 17:54, 29 December 2017 (UTC)

I stumbled upon John Emsley's Nature's building blocks on my bookshelf and it has a few things worth pointing out, which you may decide are worth while integrating:
 * total amount in body is given as 40 micrograms
 * I have not come up with a reasonable way to add this information. Given the rest of the information in the article, it rather seems a stray fact given that the element has no biological role and is not particularly notable at these concentrations.--R8R (talk) 09:49, 4 January 2018 (UTC)


 * "There is no biological role for thorium". I think the article would benefit from a clear statement like this
 * Agree. Done.--R8R (talk) 09:49, 4 January 2018 (UTC)
 * This is definitely worth saying, especially since a biological role was once suggested in mammals for uranium(!). (This is not as silly as it might sound, because unlike Th, U has long-lived daughters, and your main worry is chemical toxicity rather than radioactivity.) Double sharp (talk) 16:23, 6 January 2018 (UTC)


 * Esmark worked at was what then called the University of Christiania
 * see comment below


 * world production is in excess of 30,000 tonnes per year.
 * need to check if the figure is up to date
 * This did seem somewhat unrealistic or perhaps outdated. According to USGS, the output of the monazite concentrate was 2,700 metric tons in 2014. Added that.--R8R (talk) 12:57, 6 January 2018 (UTC)


 * known reserves exceed 3 million tonnes
 * same
 * On some thinking, I'd rather not. Given the low production, this figure is quite unrealistic because if the humanity was to recover, say, a tenth of that, prices would immediately fall and the definition of "reasonably assured resources" would yield a different figure.--R8R (talk) 12:57, 6 January 2018 (UTC)


 * 12 ppm in Earth's crust
 * This seemed like a great idea, but look at Abundance of elements in Earth's crust and the diversity of numbers. I'll rather stay away from giving a figure.--R8R (talk) 09:49, 4 January 2018 (UTC)


 * amount on Earth is about 85% of that which was present when planet formed
 * That's cool. Added.--R8R (talk) 09:49, 4 January 2018 (UTC)


 * atomic weight is 232.0381
 * As of me writing this, we have an even more precise figure in the text.--R8R (talk) 09:49, 4 January 2018 (UTC)


 * thorium oxide was used in the early days of X-ray diagnosis in 10,000 individuals.
 * Added.--R8R (talk) 09:49, 4 January 2018 (UTC)


 * These, apart from the Christiania note, are all good. Will do. We will only have to refer to newer sources. For instance, the atomic weight has been slightly changed since then, possibly so have production and reserves numbers. --R8R (talk) 17:54, 29 December 2017 (UTC)

Overall quite an impressive effort (although, as I said, I have no chemistry expertise). Edwininlondon (talk) 10:55, 24 December 2017 (UTC)
 * Edwin, thank you very much for taking the time. These are great comments and most of points raised are certainly worth addressing (DS has already addressed some of those). I will address at least some of your comments on Friday or during the weekend. At the moment, I will only note that Esmark's university was actually called Royal Frederick University at the time, and now it is called University of Oslo. It was never called University of Christiania. (Do not let this remark fool you, I find most of the remaining comments great and I'm looking forward to addressing them.)--R8R (talk) 11:57, 25 December 2017 (UTC)

I think Double sharp and I have addressed your comments. Would you check the responses?--R8R (talk) 12:57, 6 January 2018 (UTC)


 * All fine except the atomic weight. Your number may be more precise, but your source, ref #1, has 232.0381(1) I think you need a newer source. Edwininlondon (talk) 16:52, 7 January 2018 (UTC)
 * The source supported 232.0377(4); the reference actually linked to a document different than the referenced one. Thanks for bringing that up.--R8R (talk) 13:48, 10 January 2018 (UTC)


 * With the caveat that I am no expert in the field, I give my support. Good luck and hopefully one day all elements will achieve FA. Edwininlondon (talk) 21:58, 10 January 2018 (UTC)
 * Thank you! We'll try to get as far in that direction as we can.--R8R (talk) 22:19, 13 January 2018 (UTC)

Lean support Comments by Sandbh
Citing Greenwood & Earnshaw, the article says, "The 5f character of thorium is also clear in the rare and highly unstable +3 oxidation state, in which thorium exhibits the electron configuration [Rn]5f1. I checked the source and, while it lists the +3 state for Th, it does not appear to say anything else about it i.e. no rare, no unstable, and no f electron (as cool as that would be). Maybe the ion has 5f1, but trivalent compounds seem to have 6d1.Sandbh (talk) 07:00, 28 December 2017 (UTC)
 * I think the ref for this got misplaced in some recent reshuffling; I'll go back and look at some older revisions. Double sharp (talk) 03:40, 30 December 2017 (UTC)
 * Actually, I didn't need to: in the spin-off compounds of thorium (which used to be part of this article), the uncommonness of ThIII (obviously, due to the hugely negative Th4+/Th3+ standard reduction potential) is cited to Cotton's Lanthanide and Actinide Chemistry instead. Page 152 gives "The large negative values of E° for M4+/M3+ for Th and Pa indicate that reduction to form (+3) species for these metals will be difficult, whilst for U, Np, and Pu the smaller E° values indicate that both the +3 and +4 states will have reasonable stability." Page 150 lists the [Rn]5f1 configuration for the Th3+ gaseous ion.
 * Apropos of that, it gets difficult to talk about Ac in this trend, which is why I think that it really makes a lot more sense chemically to start the actinide series at Th. Starting the lanthanides at Ce can be justified, but it gets awkward to talk strictly like that because Pr and Nd are your average cerium group lanthanides and act just like La; but because 5f has radial nodes and furthermore is relativistically destabilised, the end result is that Ac with no conceivable 5f involvement looks like a complete misfit as an actinide. It looks nothing like Th through Am, which have significant chemistry in higher oxidation states. It is more at ease with Cm and Bk, but those two bear to it the relation of Ce to La, because of the importance of the +4 state (the main thing about Ac is its s-block-like inflexibility on its oxidation state, just like its younger and more stable sister La). Even Cf still has significant +4 and +2 chemistry. And then you get to Es through No which are progressively happier with the +2 state (not even Sm, Eu and Yb go as far as nobelium does in preferring it and becoming an "honorary alkaline earth metal"). So it seems that only Lr actually lives up to "actinoid" meaning "like Ac", making it difficult to stuff Ac in the trend, although it fits a trend going down from Sc and Y fairly well. But this isn't the place to argue about this issue, as inevitable as it is when group 3 is in the vicinity. ^_^ Double sharp (talk) 16:17, 13 January 2018 (UTC)

I did some copy editing in the rest of the article and added a few clarification required templates. An impressive and thorough piece of work. Sandbh (talk) 02:03, 31 December 2017 (UTC)

Support Comments from Jim
Very comprehensive, a few nitpicks Jimfbleak - talk to me?  08:34, 28 December 2017 (UTC)
 * this trend is due to the itinerance of the f-orbitals&mdash; I'm not sure what this means; it implies the f-orbitals are wandering around
 * density; actinium is lighter. &mdash;perhaps add "only" before "actinium"?
 * I think you've found a mistake! Einsteinium is divalent and is significantly lighter (8.84 g/cm3); though this may be because of radiation damage to the crystal structure when measured, a quick calculation shows that the divalent fermium, mendelevium, and nobelium should also have lower densities (see Talk:Fermium for the details). The trouble with making generalisations across the actinides is that information tends to run into a void around einsteinium, upon which our capability for making macroscopic samples runs out with four more actinides still to go. I've changed it to "Among the actinides up to californium, which can be studied in at least milligram quantities, thorium has the highest melting and boiling points and second-lowest density; only actinium is lighter.", with a note about Es. Double sharp (talk) 15:36, 28 December 2017 (UTC)
 * It is one of only three radioactive elements (along with protactinium and uranium) that occur in large enough quantities on Earth for this to be possible&mdash;For what to be possible?
 * Changed to "for a standard atomic weight to be determined". Double sharp (talk) 15:37, 28 December 2017 (UTC)
 * passivation can occur, as with uranium and plutonium&mdash;earlier, you have said that the presence of thorium dioxide increases corrosion, here it's stopping it. Is this consistent?
 * It's not passivation by thorium dioxide, but by thorium nitrate, which I've now clarified. Double sharp (talk) 15:43, 28 December 2017 (UTC)
 * Thorium complexes with organic ligands, such as oxalate, citrate, and EDTA, are much more stable and tend to occur naturally in natural thorium-containing waters&mdash;Two problems here; I don't like the close conjunction of "naturally" and "natural", and the way it's written implies that thorium complexes with oxalate, citrate, and EDTA all occur in nature. I doubt that, particularly with edta, and it's not quite what the source says
 * Rephrased to "In natural thorium-containing waters, organic thorium complexes usually occur in concentrations orders of magnitude higher than the inorganic complexes, even when the concentrations of inorganic ligands are much greater than those of organic ligands". Double sharp (talk) 15:47, 28 December 2017 (UTC)
 * Is it worth mentioning in the histogram legend that the vertical scale is non-linear (I don't mind what you decide on this)?
 * Yes, I think that's useful given the small size of the text. I've added a mention. Double sharp (talk) 15:49, 28 December 2017 (UTC)
 * I've nothing else, changed to "support" above Jimfbleak - talk to me?  16:42, 28 December 2017 (UTC)
 * Thank you, though I've still got to fix the "itinerant" thing you pointed out – I've seen this wording before indeed, but looking it up in the dictionary certainly informs me that it needs an explanation. ^_^ Double sharp (talk) 23:40, 28 December 2017 (UTC)
 * Doesn't it just mean "delocalised"? --John (talk) 19:56, 5 January 2018 (UTC)
 * It does, and this is why I've held off on this one for rather longer than I'd planned: we've just informed the reader that the increasing melting points from Fr to Th are due to having more electrons to delocalise (this is of course high-school chemistry stuff), but now we're telling them that the decreasing ones from Th to Pu come from the delocalisation of the f-orbitals and the increasing 5f-6d hybridisation causing the formation of directional bonds in the metal. (Funnily enough this covalent-bond explanation has also been applied to the high melting points of the 5d transition metals.) The electronic structures of the early actinides (Pa through Pu) are really not simple and I'm going back through the papers to see how I can re-explain this in a way that won't lead to hands being raised in the classroom. ^_-☆ Double sharp (talk) 04:09, 6 January 2018 (UTC)
 * I have removed this bit, leaving just "After thorium, there is a new downward trend in melting points from thorium to plutonium, where the number of f electrons increases from about 0.4 to about 6: this trend is due to the increasing hybridisation of the 5f and 6d orbitals and the formation of directional bonds resulting in more complex crystal structures and weakened metallic bonding." The reason is that the delocalisation of the 5f orbitals is not really relevant here; it does happen, but any effects from it are swamped by the 5f–6d hybridisation. Both are consequences of 5f being more valence-like than 4f, which people are quick to attribute to relativity, but is also because 5f has radial nodes that 4f doesn't), but I don't think we need to go that far down the rabbit hole for the Th article.
 * BTW, the same thing happens in the lanthanides: here 4f is drowned into the core very quickly and only Ce ends up with an anomalously low melting point, because from Pr onwards only 5d and 6s are contributing. The dip at Eu and Yb is partly due to there only being two delocalised electrons instead of one, but the other factor is that now that 5d is empty there is no hybridisation at all since only 6s is contributing, resulting in melting points not so different from that of Ba. The situation for Mn in the 3d row is a bit different, as the weird crystal structure is not because of hybridisation but the need to try and maximise both the magnetic spin moment (Hund's rule) and the bond-strength. (Magnetism isn't an issue for Tc and Re, which have normal crystal structures; it only becomes one in the 3d row.) Now I think the curious students are satisfied and the not-so-curious students won't be confused. ^_^ Double sharp (talk) 16:16, 6 January 2018 (UTC)
 * (The TL;DR version is that I think this has been addressed now.) Double sharp (talk) 15:06, 7 January 2018 (UTC)

Support from Smerus
OK I now know a lot about thorium I didn't know before. The article seems very thorough and it's clearly written. I can't think of anything I would want to know about thorium which isn't covered. So for what it's worth from a non-scientist like me, you get my support. -- Smerus (talk) 11:37, 29 December 2017 (UTC)
 * Thank you very much, Smerus! Double sharp (talk) 15:57, 30 December 2017 (UTC)

Sarastro (talk) 22:22, 19 January 2018 (UTC)
 * The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.