Wikipedia talk:WikiProject Chemistry/Archive 53

Are spiro a type of polycyclic?
User:CrafterNova's categorization work on commons helped uncover some inconsistencies in our hierarchy of structure-classes as we analyzed the structure of PR toxin. "Polycyclic compound" identifies itself as including tethered, fused, spiro, and bridged. "Bicyclic molecule" says the rings must be "joined" and specifically includes fused, spiro, and bridged. It does not specifically mention tethered, but nomenclature rules treat, for example, biphenyl as a single system. "Spiro compound" agrees that a simple spiro is a bicyclic. But Tricyclic and Tetracyclic state that these categories are only for fused-rings.

The 1993 IUPAC recommendations had fused, bridged, and spiro among the subcategories of polycyclics.. Starting with the 1999 recommendations and continuing to the 2013 recommendations do not have a unified "polycyclics" nomenclature category and instead have "spiro" and "fused and bridged" as two main categories, but the introductory matter includes spiro with other types of polycyclics and as part of the unified term "ring system".

Is this the correct current hierarchy, with two independent types of descriptors? and a compound or substucture has one number-of-rings and one or more type-of-connections? As an application, that would mean PR toxin (fused–fused–fused–spiro) is tetracyclic (what led to this discussion) and our tricyclic and tetracyclic articles' definitions need to be updated. DMacks (talk) 19:12, 4 January 2023 (UTC)
 * Cyclic
 * Number of rings
 * Monocyclic
 * Bicyclic
 * Tricyclic
 * Tetracyclic
 * Type of connection
 * Bridged
 * Fused
 * Spiro
 * Spiro
 * Some spiro compounds are polycyclic, while some are not.
 * The article polycyclic compound says:

a polycyclic compound is an organic compound featuring several closed rings of atoms, primarily carbon.
 * Generally, I think that a polycyclic is one that has 3 more rings, whether they are fused or bridged or spiro.


 * About whether non-fused rings count towards a compound being tricyclic or tetracyclic; sometimes some compounds having 4 rings are still classified as tricyclic.


 * Homopipramol is a tricyclic compound which has 4 rings, and 3 of those rings are fused.


 * On the other hand, sometimes some compounds having 3 fused rings and 1 tethered ring are still classified as tetracyclic.
 * Ciclazindol is a tetracyclic compound which has 3 fused rings and 1 tethered ring.

&mdash; CrafterNova  [ TALK ] [ CONT ] 07:52, 5 January 2023 (UTC)

New policy discussion
Hi so I have started a discussion for an idea into introducing a policy as part of WP:NOT to make it clear that wikipedia is not a database. This is relevant as I believe this project would not accept a database entry alone as enough for notability, yet some projects would. As such I think a clear consensus on Wikipedia's position on this is needed. You can see the discussion here EvilxFish (talk) 13:50, 13 January 2023 (UTC)

Units of measure are a bit messy
Chemistry-related articles are inconsistent in their use of units of measure. As far as I can see, the infobox default is to use SI units only or SI units plus conversions to non-SI. But some articles use non-metric units only. In some articles, for example, vapour pressure is expressed in pascals only and in mmHg only. Viscosity is sometimes in pascal·seconds only and sometimes in centipoise only.

The inconsistency can be resolved by bringing each infobox into line with guidance at MOSNUM.

Does anybody object?" Tony (talk)  10:45, 14 January 2023 (UTC)


 * In general, applying Convert is preferred at enwiki, I assume.
 * Do we understand:
 * - for each quantity value, apply Convert?
 * - first value system in (metric/SI/imperial) should be consistent throughout article?
 * - or, put unit system of the source first?
 * - are there units excvluded for some reason (eg, converted unit not common enough)?
 * Or do we say: apply source-based thoughout, go ahead; these issues tb fleshed out later?
 * BTW, please ping me if there are concerns wrt temperatures of melting point/b.p./flashpoint/autoignition: they have auto-conversion (nice I guess). DePiep (talk) 11:07, 14 January 2023 (UTC)
 * Does Convert cover viscosity? I can't seem to find it... Torr is easy to convert, I suspect editors are just adding values as they are presented in the literature. mmHg is very common, I remember using McLeod gauges up until the 2010s. --Project Osprey (talk) 17:35, 14 January 2023 (UTC)

PhotoX articles
In case anyone has time and expertise, our photochemistry articles need help and so do I in terms of my understanding. There's these articles: My message does not offer any resolution except as a request for help on getting definitions nailed down. --Smokefoot (talk) 18:47, 16 January 2023 (UTC)
 * photocatalysis, as the term implies and as IUPAC confirms, is chemistry that is catalytic in photons. The excited state species (a sensitizer) races around, causing many reactions.  The present article does not seem to embrace that definition. The other problem is that this article does not show many balanced equations, so it is very difficult to discuss catalysis without balanced equations. Now, however, I am starting to think that most photocatalyzers use a looser definition where the TON per photon is actually ≤1, and the excited species induces maybe one reaction, returns to its ground state poised to accept another photon again.  It is a catalyst that requires photons.  Most of us call such an entity a sensitizer or photosensitizer. But we have a separate article on that topic.
 * photosensitizer refers to photocatalysis but the article is again a collection of mechanistic and functional themes, including photodynamic therapy. I think that photocatalysts and photosensitizers are the same thing.
 * photoredox catalysis, a raging area of organic chemistry. The Wikipedia article is sprawling and needs help, partly because it is often a collection of factoids vs an encyclopedic overview.

FAs last reviewed from 2004 to 2007 of interest to this WikiProject
If you review an article on this list, please add commentary at the article talk page, with a section heading == URFA/2020 review== and also add either Notes or Noticed to WP:URFA/2020A, per the instructions at WP:URFA/2020. Comments added here may be swept up in archives and lost, and more editors will see comments on article talk. Sandy Georgia (Talk)  21:10, 20 January 2023 (UTC)
 * 1) Enzyme kinetics
 * 2) Francium
 * 3) Joseph Priestley
 * 4) Nicotinamide adenine dinucleotide
 * 5) Oxidative phosphorylation
 * 6) Uranium
 * 7) Xenon

undo redirect from dissolution to solvation
A proposal initially put forward by saw the page for dissolution be merged with solvation. I was going to undo this following WP:bold but I think it may be more appropriate to discuss it here first. The reason I propose undoing this is two fold:

1) dissolution and solvation are not equivalent and treating them as such may lead to confusion or worse giving people false information they are.

2) dissolution as a topic although covered badly (because the article focused on solvation previously) is notable in its own right for example it is covered here, some reaction mechanisms here may also be useful and for the mathematics behind it a range of publications will discuss the Noyes-Whitney equation. I grant that it is easy for the two topics to overlap and we should be careful about that but argue there is enough to justify a standalone article.

I look forward to hearing your thoughts! EvilxFish (talk) 08:04, 14 January 2023 (UTC)
 * Thank you for the notice. No strong views here about undoing my split or merge or whatever. The goal is article improvement, however tortuous.
 * Agreed with EvilxFish that solvation and dissolution are not equivalent. They are at least semi-closely related.  I do not recall the history of these articles, but my style is often to merge two semi-crappy articles into one semi-decent one provided that the themes are closely overlapping.
 * My one complaint is that the term "dissolution" is often used loosely. "Iron oxide dissolves in nitric acid" would be a typical comment, but of course iron oxide is destroyed by the process.  Now, one can get lawyery about this topic, Sodium chloride dissolves in water? Not really in some respects, it converts to [Na(H2O)6]+ and Cl-.  But at least one recovers NaCl when the solution is evaporated.  But if one were to isotopically label Na and Cl, the labels would be scrambled. For the same (litigious?) logic, it is questionable to claim that oceans contain NaCl.  Blah, blah, blah. --Smokefoot (talk) 18:41, 26 January 2023 (UTC)

Linking Chembox to spectroscopic data on the AITS database
AITS maintains the Spectral Database for Organic Compounds SDBS, which is an open access directory of NMR, IR, and MS data covering at least 34,000 organic molecules. The one thing our pages lack is spectroscopic data, so creating a parameter for linking to SDBS in chembox seems like an obvious improvement. Over the years a various efforts have linked Chembox up to CAS, Chemspider, PubChem and recently CompTox. Often this has been done in an automated or semi-automated way. I haven't the skills to do something like that, but I think it would be an undertaking with obvious merits. Project Osprey (talk) 00:08, 18 January 2023 (UTC)


 * The SDBS is searchable but the simplest unique ID that can be used is the CAS number, which we already have in our chembox. I can't see any merit in adding their unique ID (the SDBS No) as that wouldn't give our readers any additional functionality. I assume you aren't thinking we should expose any actual raw data such as IR peak information, which would be very difficult to select because there could be so much of it. On the other hand, if we could determine behind-the-scenes from the CAS number that there was indeed an entry in the SDBS, it would be nice to automatically add the link. As an example, I'm suggesting that for pyridine we would include something like SDBS spectral data somewhere in the properties box. Mike Turnbull (talk) 11:49, 18 January 2023 (UTC)


 * Yes, that's exactly what I'm thinking. A link in the 'Properties' section rather than 'Identifiers'. The SDBS unique ID is irrelevant to our readers, but a link to some spectroscopic data would nice. --Project Osprey (talk) 12:05, 18 January 2023 (UTC)
 * This sounds useful. Perhaps if it has a link in Wikidata, it could be done automatically. I added it for pyridine, so perhaps Wikidata has a lot of these missing. Graeme Bartlett (talk) 20:54, 18 January 2023 (UTC)
 * So far: a chemical can have a page with spectral data in the SDBS database. Key (identifier) in that database is CAS RN. Using CAS RN, an internal database ID is not needed. Proposal to add this external link to the, as it links to otherwise non-provided spectral info. Questiion: how to detect that the chemical/CAS_RN has an entry in SDBS. Second route to explore: use wikidata to check external link.
 * In Wikidata: en:SDBS R &rarr; =, Wikidata property =.
 * Exampe: pyridine =, has P5926: &mdash; voila, your link.
 * Later more (implementation proposal). -DePiep (talk) 23:49, 18 January 2023 (UTC)
 * I have no opinion on necessity of adding this indo, I cannot judge. -DePiep (talk) 07:55, 19 January 2023 (UTC)

Proposal to add SDBS spectral information (external link)

 * Proposal to add information: add to and Infobox drug the external link to the SDBS-database (as maintained by AITS). Multiple substances may give multiple links. Default reading from Wikidata (d:Property:P5926). Local option at enwiki to (a) overwrite and (b) suppress the link. -DePiep (talk) 09:53, 20 January 2023 (UTC)
 * Support, since spectral information is not yet available. Happy with the Wikidata curation route. -DePiep (talk) 09:55, 20 January 2023 (UTC)

Implementation

 * Proposal: implement SDBS external link in Chembox by automated reading Wikidata.
 * Usefulness: see above (OP): external link to spectral data, not otherwise provided by Chembox.
 * Wikidata advantage: mass curation for chemicals. (As opposed to enwiki manual entrance for either ID or T/F existance).
 * Local options: (enwiki) optional to manually overrule this WD, by a parameter 999, or suppress the link by none.
 * In Infobox : in section Identifiers, ordered between .. and .. [tbd].
 * Quantity label (LH text in ): "[tbd] (SDBS)"
 * Value text (RH text, external link): as given by Wikidata, edit-pencil icon added?
 * Usage: : 12k articles, ? SDBS links potentially.
 * Template:Chembox requires input QID1, QID2, ... once per infobox.
 * Consider Infobox drug aka : 7.8k articles;
 * Example live property this way: CompTox Dashboard (EPA) in for ammonia:, link at enwiki:.
 * SDBS: : pyridine =, has P5926: ""
 * Will prepare code in sandbox and tests/demos. TBD: LH text; position in Section. Comments? -DePiep (talk) 00:29, 19 January 2023 (UTC)
 * Sounds like a suitable proposal. Using QID1 etc for indexed sounds OK. Graeme Bartlett (talk) 01:25, 19 January 2023 (UTC)
 * Sounds like a suitable proposal. Using QID1 etc for indexed sounds OK. Graeme Bartlett (talk) 01:25, 19 January 2023 (UTC)


 * Issue: In wikidata, only five chemicals have this property. Still, I propose to add it from WD not local. Advise mass-adding to chemicals. -DePiep (talk) 00:41, 19 January 2023 (UTC)
 * Thanks,, as usual your proposal looks sound to me. Wikidata is clearly the way to go, as for DSSTox. I also like the idea of a local override using  because that can be used for instances where our chembox is multi-valued for CASNO (e.g. isomers/salts all at one entry: see thiamine for an example). Clearly, chembox and drugbox need to be handled the same way. I look forward to seeing your demo. Mike Turnbull (talk) 11:12, 19 January 2023 (UTC)
 * It should be in Chembox section: Properties (we aren't adding an identifier, we are linking to data-properties). I understand how data comes out of WikiData, but how does it go in? Will manual chembox entries in en.wiki be read by wikidata? --Project Osprey (talk) 12:08, 19 January 2023 (UTC)
 * Historically, section "Identifiers" in contains all ID's inclusing external database IDs (aka database keys). When applicable, presented as an external link (not a bare ID number). For example, recent addition "CompTox Dashboard (EPA)" was positioned there. On top of this, the SDBS identifier is not spectral info by itself (which were an argument for Properties indeed). This does not look like erronoeous to me, though improvements are possible.
 * Technically, current design does not allow indexes (like CASno2) to be reused outside of the Identifiers section. So, Properties values cannot be indexed. (This is a redesign issue, but taking away this limit is opposed to).
 * In a wider view, all external links could deserve their own location. Be it replaced inside or outside of the Infobox. Alas, this is tbd elsewhere.
 * For now, this single external link to be added to the existing list. DePiep (talk) 12:42, 19 January 2023 (UTC)
 * Understood. My concern was that the link might be overlooked there. We do link to a lot of identiferes--Project Osprey (talk) 12:53, 19 January 2023 (UTC)


 * Issue. There's a bit of a Bonnie and Clyde problem with wikidata vs enwiki for stereoisomerism that gets worse with each step further into another resource. For example, the proline article is solely about the L- isomer. Wikidata and SDBS have separate entries for L, D, L/D. It makes sense that we should be self-consistent, just like we make sure CASNo, pubchem, and chemspider links are as specific as our article's topic. On the other hand, do we lose some value by only linking the spectra that are tagged exactly as specifically as our article? It seems common for SDBS to have only some stereoisomers or different types of spectra for different stereoisomers: the only 1H for proline is D. DMacks (talk) 17:18, 19 January 2023 (UTC)
 * That is a good point. Indexed parameters were supposed to fix all, that but they aren't often used. Project Osprey (talk) 17:48, 19 January 2023 (UTC)
 * Not a big problem as all conventional spectra are identical for D, L and D/L isomers. Any well-curated spectral database should avoid diastereomeric mixtures. Mike Turnbull (talk) 12:39, 23 January 2023 (UTC)
 * My edge of understanding reached. Expect that indexing (QID, QID1, QID2, .. QID5) solves this first step. If more problematic (eg, QID's don't cover a substance this staraightforward as in proline example?), ping me. Not blocking this I understand. DePiep (talk) 18:16, 19 January 2023 (UTC)
 * Maybe this is where the  suggestion  has already made gets over the issue if we also implement the use of , as we do for other indexed parameters. Presence of any of those codes would be intended to take precedence over the automated link via (single-valued)  . Mike Turnbull (talk) 18:26, 19 January 2023 (UTC)
 * Must think once more about this. I expect like: no will notshow that datapoint (single row) for the article/QID. SDBS3 will show for QID3 (unless no). QID3 must be entered locally (in enwiki article Chembox). Complicated, but consistent logically, when setting QID (default is article-QID) into other substance QID. Anyway, later documentation must make this clear. DePiep (talk) 18:36, 19 January 2023 (UTC)


 * Prorgress report Jan 24: rough construct made, /testcases2#SDBS. More time for this in Feb. has added this ID to 99 compounds (thanks), so development is viable. -DePiep (talk) 07:53, 24 January 2023 (UTC)
 * Thanks for starting on this. It is fairly slow work adding manually. I have added 1-carbon fluorine containing chemicals, and inorganics with the lowest formula weight. Of course the database is mostly organic. (I expected that the value would be put in the properties section rather than identifiers) (Also CASRN is not 100% right in Wikidata. I had to remove a RN that did not match the Wikidata in this exercise.) There are also some spectra entries for radicals and atomic elements that we don't have wikidata for. Eg Br atom is not the same as Br2 spectrumwise. Graeme Bartlett (talk) 09:43, 24 January 2023 (UTC)
 * Thank you both. This was my idea so I would like to help, but wikidata is a mystery to me. How can I add data there? SDBS also uses InChI, which might be better than CAS?--Project Osprey (talk) 10:13, 24 January 2023 (UTC)
 * Yes, manually is though. WD is best suited for mass curating, but needs some data dump. (d:Help:QuickStatements is my starter; ask if you want more hints).
 * My only worry is, that you end up saying "I'd prefer editing enwiki for this" ... ;-) DePiep (talk) 10:21, 24 January 2023 (UTC)

Wikidata SDBS curation

 * (refactoring; some earlier posts moved here -DePiep (talk) 13:04, 19 January 2023 (UTC))
 * @Project Osprey I assume that a well-known someone will use a database search to pull out CASno-SDBSno pairs from SDBS and load them to Wikidata by matching CASno. This is certainly a job for automation, not one where you have to start with manual entries in chemboxes. That's how I presume it was done for DSSTox links. Mike Turnbull (talk) 12:35, 19 January 2023 (UTC)


 * DSSTox was in part driven from the outside, the set-up with CAS also involved an organised data-dump, although I seem to recall that had something to do with that. --Project Osprey (talk) 12:53, 19 January 2023 (UTC)
 * I just checked, and if you search at this SDBS URL, placing a wildcard % in the SDBS No field and choosing to sort the output by SDBS No, you get essentially the whole database of 35331 hits in pages of 100 hits. Unfortunately, the CASNO is not one of the default columns on the output or even I could scrape the relevant data! I'm sure that the database curators would be happy to part with the information if contacted with a "pretty please". Mike Turnbull (talk) 12:55, 19 January 2023 (UTC)
 * If nobody else has done so, I can contact them. Their license seems open enough for us to link to them but not to bulk-import any of the data, and their site API looks great for linking via SDBS number. DMacks (talk) 17:24, 19 January 2023 (UTC)
 * Agreed. Bulk importation would be silly, as WP:NOTDATABASE and we just want to give readers a link to a curated source of reliable data. Thanks for the offer to contact them: maybe once DePiep has shown the basics are feasible? Mike Turnbull (talk) 18:18, 19 January 2023 (UTC)
 * 2cents. I understand any bulk dump would be entered into Wikidata as P5926 by CASRN. I don't think that is a NOTDATABASE question, it's what WD in core (also) is. DePiep (talk) 18:25, 19 January 2023 (UTC)

Cautionary note
I was thinking again about the implementation of this suggestion. AIST have about 35k records that are well curated. It occurs to me that Pubchem has potentially vastly more records than that, which at face value are probably as valid. For example, pyridine is at this pubchem URL and seems pretty similar to the AIST entry here. So I'm a bit worried that we are trying to implement something that could equally well be implemented just by adding #section=Spectral-Information to the Pubchem URL that is already linked in the chembox and which we would put separately in the properties section. I've raised this with (see User_talk:Project_Osprey) but would like views from others who have contributed here:  and  especially, before we increase the workload for. Mike Turnbull (talk) 22:18, 25 January 2023 (UTC)
 * People can already use PubChem without any additional effort as we put an effort into getting the CID in the infobox. I don't think it would be worth adding a section link, as someone would still have to check if the section existed on the PubChem page. I am also unconvinced that the PubChem info is as well curated as AIST (based on my effort to get a correction!). But if someone wants to check correctness out, go ahead. Graeme Bartlett (talk) 22:29, 25 January 2023 (UTC)
 * Good thought. TL;DR: quantity (wording) "spectral" to add somehow; good info access/presentation counts; what with similar property situations; best sourced; automatable check for presence (PubChem?).
 * We should go for the best information full stop, which includes well-sourcedness, accessability, readyness, presentation. Both in Infobox and external site.
 * Now, I understand PubChem has this section, but even expert/interested OP PO was not familiar with. What would a Reader expect, how much search effort would a Reader do before leaving this Wiki (disappointed)?
 * And, isn't this with many more properties and at various chem databases? (I recall hazards/H&S data, at Aldrich). Ideas from those? Is it possible to present some actual spectral data in here? I think to have the word "Spectral" at least once in the lefthand (quantity) column is good.
 * As for curation: sourced website should take precedence. (Personally, I remember in 2016 PubChem had different molar masses, calculated from different standard atomic weights. These ended up in Wikidata. Complicated because of handling uncertainties. Looks like PubChem has improved/corrected this).
 * What GB says: how to know that Pubchem actually has that section? (For now, think this would be a stopper for PubChem). Also a reason & stimulation to curate this data at Wikidata ourselves.
 * Please, you experts, keep fleshing out. (About past effort: don't worry, happy to improve). DePiep (talk) 07:33, 26 January 2023 (UTC)
 * My personal feeling is that good data is better than bigger data. SDBS might hold few datasets than PubChem (or others), but the benefit is that they appear to have been collected by a single group of experts. I expect many spectra published in the literature are collected by undergrads and so quality there can vary. That's just an opinion though. --Project Osprey (talk) 21:35, 26 January 2023 (UTC)

Structural drawings by Mplanine
Ball-and stick images have recently been added to many Wikipedia's chemistry articles by user:Mplanine. No doubt intentions are positive, but I suggest that most are not useful and some are misleading, such as implying particular conformations of floppy molecules. But my main concern is that these images convey nothing beyond what a good ChemDraw shows. The naive reader might be impressed by the attractive graphics, but the perception is misleading and dangerous. Other contributors of artwork seem to be more selective about which images are notable, and they also tend to use crystallographic coordinates for images. --Smokefoot (talk) 15:21, 2 February 2023 (UTC)


 * has added drawings which look like the sort of images in the Cambridge Structural Database. However, they are not in fact based on these data. For example, the conformation of his drawing at physostigmine is not the same as its entry on the database. I agree with  that such images are rarely helpful: we already have standard line drawings in our Chemboxes. Mplanine might be using his time more productively by adding the relevant citations for the CSD structures and avoid straying into original research. Mike Turnbull (talk) 16:15, 2 February 2023 (UTC)

Project-independent quality assessments
See Village pump (proposals). This proposes support for quality assessment at the article level, recorded in WikiProject banner shell, and inherited by the wikiproject banners. However, wikiprojects that prefer to use custom approaches to quality assessment can continue to do so. Aymatth2 (talk) 20:39, 6 February 2023 (UTC)

Good article reassessment for Atomic theory
Atomic theory has been nominated for a good article reassessment. If you are interested in the discussion, please participate by adding your comments to the reassessment page. If concerns are not addressed during the review period, the good article status may be removed from the article. Onegreatjoke (talk) 21:14, 7 February 2023 (UTC)

Good article reassessment for Brønsted–Lowry acid–base theory
Brønsted–Lowry acid–base theory has been nominated for a good article reassessment. If you are interested in the discussion, please participate by adding your comments to the reassessment page. If concerns are not addressed during the review period, the good article status may be removed from the article. Onegreatjoke (talk) 21:21, 7 February 2023 (UTC)

Good article reassessment for X-ray crystallography
X-ray crystallography has been nominated for a good article reassessment. If you are interested in the discussion, please participate by adding your comments to the reassessment page. If concerns are not addressed during the review period, the good article status may be removed from the article. Onegreatjoke (talk) 21:30, 7 February 2023 (UTC)

Good article reassessment for Oligonucleotide synthesis
Oligonucleotide synthesis has been nominated for a good article reassessment. If you are interested in the discussion, please participate by adding your comments to the reassessment page. If concerns are not addressed during the review period, the good article status may be removed from the article. Onegreatjoke (talk) 22:18, 7 February 2023 (UTC)

Good article reassessment for Amino acid
Amino acid has been nominated for a good article reassessment. If you are interested in the discussion, please participate by adding your comments to the reassessment page. If concerns are not addressed during the review period, the good article status may be removed from the article. Onegreatjoke (talk) 22:17, 8 February 2023 (UTC)

Good article reassessment for Persistent carbene
Persistent carbene has been nominated for a good article reassessment. If you are interested in the discussion, please participate by adding your comments to the reassessment page. If concerns are not addressed during the review period, the good article status may be removed from the article. — Preceding unsigned comment added by Onegreatjoke (talk • contribs) 22:13, 9 February 2023 (UTC)

Organophosphorous
Are Organophosphates and Phosphite esters organophosphorous compounds? Baring in mind that they have no P-C bonds. Project Osprey (talk) 09:37, 16 February 2023 (UTC)
 * Our category system says they are organophosphorus compounds. Organophosphorus chemistry allows non P-C bonding. But I don't think that Organophosphorous (a spelling error) should redirect to Organophosphate. Graeme Bartlett (talk) 10:53, 16 February 2023 (UTC)
 * The definition organophosphorus is a recurring issue. We might seek to agree on some definition and stick that agreement into an MOS.
 * Some chemists might like to insist that there be a P-C bond in an organophosphorus, but the real world seems to define the class of compounds more broadly.  Nerve agent skillfully uses the term organophosphates and avoids organophosphorus (sarin is both).--Smokefoot (talk) 14:25, 16 February 2023 (UTC)
 * I would agree that segregating them is pedantic and unhelpful. I am tempted to include a brief note at the relevant pages. "Although they do not contain P-C bonds, phosphate esters are commonly regarded as organophosphorous compounds", or suchlike. --Project Osprey (talk) 14:44, 16 February 2023 (UTC)

Adding Cambridge Structural Database identifiers to Chembox
Greetings! I work at the Cambridge Crystallographic Data Centre, where we are beginning to link WikiData entities to Cambridge Structural Database (CSD) entries. The first stage (~400 entries from the CSD Teaching Subset) is complete and the second stage (~39000 CSD organic-only entries linked to 27500 WikiData entities) should be added soon. Would you consider using this to add links to the relevant Wikipedia entries in the Chembox? Any feedback about this idea would be appreciated, as well as any support from this community with future implementation. CDSCCDC (talk) 16:30, 21 February 2023 (UTC)


 * Hello, I'm David at CCDC and I've abandoned the CDSCCDC account in case it was unclear that this is a single person account. I have disclosed my paid status on my new Userpage.
 * @CDSCCDC This is an interesting idea which triggers a number of thoughts for me. I should say that I'm supportive, although some of my comments may sound negative.
 * A compound like ritonavir (in the teaching set) has multiple entries in the CSD, so how best to deal with this? YIGPIO03 seems to be the enzyme-bound drug, which may or may not be the "best" set of coordinates. Wikpedia's chembox already includes a ball-and-stick drawing created by from YIGPIO02. Is there a way to generate these drawings from the "official" CSD entry so that the link and the drawing would correspond? Maybe with less work needing to be done by editors who regularly do this (another of whom is )?
 * How would you propose to handle the worst case of one-to-many, which is ROY with at least 13 CSD entries?
 * We use Chembox_Structure for crystal data (when available and if someone adds it). Would it be possible to populate its parameters automatically given the CSD link? This seems the best place to place the link once we decide how to solve the one-to-many issue.
 * Some organic crystal structures are for salts of the parent compound, hence may strictly not be the material the chembox describes. What would be our policy on using these data if this were the only available structure?
 * Mike Turnbull (talk) 17:18, 21 February 2023 (UTC)
 * Responding to Mike Turnbull:
 * All entries in the CSD are assigned a "refcode", and the scheme is to put all identical compounds into the same "Refcode Family". So for paracetamol/acetaminophen the first entry is HXACAN, the next is HXACAN01, then HXACAN02, etc. I am genuinely unsure if this is deliberate or not, but if you search for the first member of the refcode family it will return all members of the family. So for your example of ROY, in practice you could use our persistent identifier for the first member of the refcode family and it will provide access to all of them: identifiers.org/csd:QAXMEH. I have to say though that because of some decisions that were made in the dim and distant past, this solution is not necessarily universally available.
 * Regarding the provision of 3D structures, we have already been considering adding some to WikiData. However, I understand there are difficulties due to the choices in format for 3D visualisations we have made in the past. If there is a consensus that it would be useful then I can try to get a better understanding of exactly what the problem is.
 * I don't know whether it would be possible to directly supply crystal data from the website, but I think that we would probably not have a problem in theory. We have been advised not to add crystal data to WikiData since the data is available from us, but if we knew a specific subset for which the information would be shared through Wikipedia I think we could justify adding it to WikiData and you can take it from there.
 * We are focussing on only single-component crystal structures for now because we want to walk before we try to run. However, we are also actively pursuing links with other databases where we are in favour of trying to link compounds with crystal structures containing a salt form or solvated form, since in practice this can be the only way of actually producing a crystal.
 * The dog that hasn't barked yet (as far as I can tell) is the issue of polymorphs. Would there be the ability and the willingness to include multiple Chembox_Structures for chemicals with more than one crystal structure?
 * David at CCDC (talk) 23:21, 22 February 2023 (UTC)
 * FWIW, here are the 1292 articles using section. HTH -DePiep (talk) 17:36, 21 February 2023 (UTC)
 * (ec)
 * We can do that. I hope some editors familiar with the topic can write support / discussion here on adding the info. (I myself am not).
 * Reading from Wikidata into Chembox example: CompTox Dashboard (EPA), see ammonia. This data is read primarily from WD (with local enwiki overwrite option), so that the mass-curation at WD is used to the max. (no need to update enwiki articles). Also, we can index data, so it can handle five chemicals (by QID). Infobox drug will have the same treatment. (Chem+Drug = 11942 + 7846 = 19788 articles).
 * Question (for CDSCCDC?): wich property ID to use? I see two:
 * WD: has
 * Response: CSD Refcode is preferred. Not everything in the CSD has a CCDC number (either entries that predate the deposition system or were identified in the literature without being directly deposited) and not everything with a CCDC Number is in the CSD (ICSD entries, or structures created by Crystal Structure Prediction), but all CSD entries will have a Refcode.
 * David at CCDC (talk) 23:21, 22 February 2023 (UTC)
 * The bad news is: I hardly have time to promis any action in this for the next few weeks. Already AITS (ADBS) is waiting to be added similarly, and my desk is covered with isotopes. But first: what do you editors think?
 * -DePiep (talk) 17:33, 21 February 2023 (UTC)
 * I welcome objective, broadly useful information that is widely available (vs paywall), so I support linking CSD identifiers to ChemBoxes. Some specialized questions are raised above, such as the many duplicate structures (also my regret that many important structures are missing from CSD because those papers are older than CSD, but that complaint is tangential to this discussion).  Just a few more points:
 * -DePiep (talk) 17:33, 21 February 2023 (UTC)
 * I welcome objective, broadly useful information that is widely available (vs paywall), so I support linking CSD identifiers to ChemBoxes. Some specialized questions are raised above, such as the many duplicate structures (also my regret that many important structures are missing from CSD because those papers are older than CSD, but that complaint is tangential to this discussion).  Just a few more points:


 * what is the possibility that CSD decides to demand a fee for access?
 * remind CSD that Wikipedia, while a major educational resource, is not a textbook, and we avoid giving instruction per WP:NOTTEXTBOOK.
 * we must be on guard lest we clutter up pages with facts that are undeniably true (like a crystal structure) but are of questionable value (like the crystal structure of many/most complex organic compounds, which are apparent from the octet rule).
 * on that topic, where crystallography is more important is in the area of pure inorganic chemistry, the database which is handled separately from CSD. These structures often cannot be predicted from the octet rule.--Smokefoot (talk) 21:54, 21 February 2023 (UTC)
 * Re: fee for access, I believe the chances are slim to none. I think it is recognised at CCDC that we are custodians of the data, and while we may sell services based on value we have added to support the CSD, the original data should be available free of charge. David at CCDC (talk) 23:21, 22 February 2023 (UTC)
 * A few thoughts:


 * I agree a CSD entry field in ChemBox would be a useful option to have. Whether it should be used in any given article is a decision for editors to make on a case-by-case basis.


 * I would strongly discourage trying to automatically generate the main 2D or 3D images of a compound from CSD data. There might be more than one molecule in the asymmetric unit (e.g. HUVXIF for methohexital), or infinite structures (e.g. UDOREM02 for sodium bicarbonate), or salts/solvates/co-crystals where only one component is relevant to the article (e.g. XIZNOM for promethazine), or simply an awkwardly shaped molecule that looks cluttered unless you orient it a certain way (e.g. KIPLIG for valsartan). These cases arise so often that editorial judgement is almost always required on which parts of a crystal structure to show and how. I wouldn't want there to be less work in this area, I believe the care taken to curate and optimise these images creates great value in Wikipedia. No other reference work has as many skilled editors able to do this manual work for as many articles.


 * I disagree that molecular structures are trivial to deduce from the octet rule. Crystal structures usually provide a simple but very important piece of information: that the structure of the compound is what we think it is. An example of this is aldosterone – despite most textbooks drawing it as an aldehyde, it's actually an acetal. Similarly for adrenaline and other somewhat counterintuitive zwitterions. And the precise molecular conformation is not a trivial thing to compute, either mentally or in silico. A simple 3D diagram of a molecule's structure is often the most accessible aspect of a chemistry article to a general audience. We do not expect them to deduce the structure from the skeletal formula, itself tricky to interpret for readers who haven't studied chemistry beyond, say, age 16. These are two of the main reasons I add crystal structures to articles: because structures often have unexpected features and readers don't understand skeletal formulae.


 * There are many purely inorganic structures in the CSD thanks to its recent collaboration with the ICSD. For example, CSD entry 1722034 for potassium nitrate, which is ICSD entry 281552. Not all of ICSD seems to be there, though, and it's much harder to search for these inorganics through the Access Structures interface.


 * All my (recent) images based on CSD data have links to the corresponding entry in WebCSD in the image description page, so we could scrape them (and those of other editors who do the same). The caveats everyone has pointed out mean some serious quality control would be needed before adding these links to ChemBoxes.


 * I am happy to get involved in this task. As Wikipedia editing is voluntary, it would be ideal if the work could be done in dribs and drabs as editors have time and inclination. That would open it up to wider participation.


 * Ben (talk) 08:43, 22 February 2023 (UTC)
 * Re: CSD and ICSD, I will be a bit pedantic here and say that while we have a joint deposition system and both databases are accessed through the same interface, they are actually separate databases and the CCDC cannot make decisions about sharing ICSD data. David at CCDC (talk) 23:21, 22 February 2023 (UTC)


 * I appreciate this message from user:CDSCCDC. Although I make use of this database frequently, it is not organised to be indexed by substance. Instead it is organised by publication. So each time a structure is published it can get an entry in the CCDC. It could have entries linked in a one Wikidata to many CCDC entries. It could also be linked to the publication reference entries in Wikidata. Because of the one to many nature it won't be simply possible to just populate a structure box. But should have a human in the loop to figure out which entry to use. Which entries are at standard conditions (or conditions that make sense to our articles), and which entry is the most reliable? (much tougher to tell). However it would be good to have some tools to generate a structure box from a CCDC entry. I have two tabs for the database open on my browser right now. One is https://www.ccdc.cam.ac.uk/structures/search?id=doi:10.1007/s12039-017-1224-3 for CSD Entry: ZEMWUM. From the presented screen I can tell space group and unit cell dimensions. But there is more information hidden in the .cif file that can be downloaded. This includes colour, formula units, density, crystal system, unit cell volume, and temperature. So is there a way to more simply present that .cif data so that templates here could be generated? Answering the original question, if the selected entries are curated to be excellent entries, then they would be good as reference information in Wikidata for structure info. So they could be safely added. Graeme Bartlett (talk) 09:22, 22 February 2023 (UTC)
 * Thanks for the clarification. Any need for human intervention (linking "confirming" Wikidata QID to a chembox substance; disambiguate in the 1:n relation) is making data untrustworthy. enwiki has ~20k Chem+Drugboxes. We can not rely on curating Wikisata info manually any more. Also, it would defy the gain of mass-curation at Wikidata. We cannot permit adding an extra layer of verification. I hope there is an other solotion for this.
 * BTW, Graeme, I see two properties tied to CSD:,  . Could this help us? DePiep (talk) 10:40, 22 February 2023 (UTC)
 * As mentioned above, CSD Refcode would be preferred by the CCDC because it is applicable to all CSD entries, unlike CCDC number. David at CCDC (talk) 23:21, 22 February 2023 (UTC)


 * Support. And the experimental condition (temperature, etc.) and the corresponding space group should be covered in the parameters of Chembox. --Leiem (talk) 09:45, 22 February 2023 (UTC)
 * Responding to Ben and others:
 * Yes, there are cases where an organic structure cannot be anticipated from octet rule. Of the millions of organic compounds, that predicament is inevitable. But the percentage is very low. For that reason, organic structures from theory or crystallography are rarely any improvement over a good ChemDraw.  But my view is probably in the minority.
 * The other point is that I suspect that we and others misuse the term "crystal structure", which I think is about packing, not the 3d structure of a molecule/ion. Packing in organic chemistry is rarely of interest since most of the properties of interest arise in solution (where structure is almost always retained BTW).  CSD people might have some clarification.  Crystal structure does not address this point nor does the Gold Book.
 * But it seems that we all welcome CSD involvement.--Smokefoot (talk) 14:35, 22 February 2023 (UTC)

What's this bond symbol?
In File:Progoitrin.svg, there's a C=N double bond that looks just like what I learned in chemistry 101. But https://pubchem.ncbi.nlm.nih.gov/compound/progoitrin shows that bond with a different symbol, two crossed lines. What does that signify? I'm guessing something to do with plane of rotation, but what makes that bond so special that it's show differently?

Hmm, I see the same symbol for Glucoputranjivin, Glucotropeolin, and a bunch of other similar compounds. -- RoySmith (talk) 19:55, 24 February 2023 (UTC)
 * It's a double bond with uncertain or mixed E/Z isomerism. See the last paragraph+image at Skeletal formula. DMacks (talk) 20:04, 24 February 2023 (UTC)
 * @RoySmith Very often Chemspider has better curation of the exact sterochemistry, so that glucotropaeolin, for example, is shown as the E form, despite the fact that our article currently shows the Z form. The InCHI key=QQGLQYQXUKHWPX-BXLHIMNRSA-N is for the E form. I'm going to revert the image at Commons:File:Glucotropaeolin.svg to the version originally uploaded, which has the correct geometry, confirmed also by CAS. Mike Turnbull (talk) 21:33, 24 February 2023 (UTC)
 * Actually, it is more complicated! Both E and Z forms are in Chemspider etc and I'll need to check the original literature to confirm which is really glucotropaeolin. The alternative InChI key is QQGLQYQXUKHWPX-RFEZBLSLSA-N. Watch this space.... Mike Turnbull (talk) 21:43, 24 February 2023 (UTC)
 * @RoySmith I've now expanded and tidied up glucotropaeolin and begun to look at all articles on the related glucosinolates. A 2020 review 10.1016/j.phytochem.2019.112100 makes it clear that these natural products are all of Z geometry but many standard databases have multiple entries that make a mess: Wikidata is no exception and I'll try to sort that out in due course. Thanks for raising the issue! Mike Turnbull (talk) 17:10, 27 February 2023 (UTC)
 * Thank you all for your help! -- RoySmith (talk) 17:12, 27 February 2023 (UTC)

Polypropylene polybenzyl isocyanate
The references for this article appear to be entirely unrelated to the content. Maybe I'm completely misunderstanding something, so could someone else take a look and see if they agree or not? All the references were added in a single edit 15 years after the text was written, which seems odd to me too. Marbletan (talk) 19:54, 7 March 2023 (UTC)
 * Agree, none of the references are related to this topic. We could ask user:RowanJ LP who added these cites to check them out. Others that Rowan added to other articles, including chemistry topics, the same day appear OK. Graeme Bartlett (talk) 22:44, 7 March 2023 (UTC)
 * The page is virtually an orphan and the term "Polypropylene polybenzyl isocyanate" returns only 9 hits in Google Scholar. The page states that it is a polyurea, but that is at odds with the given chemical name. The similarly named "Polymethylene polyphenyl isocyanate" (essentially an oligomeric form of MDI) returns many more hits. Both compound are abbreviated PPI, which might lead to confusion. Project Osprey (talk) 09:40, 8 March 2023 (UTC)
 * It was the name "Polypropylene polybenzyl isocyanate" that brought my attention to the article in the first place. I couldn't parse that as a meaningful chemical name.  After reading the article, I still can't.  I searched SciFinder and got no scientific journal hits on that name.  It's possible that the few Google hits on this term have merely originated from this Wikipedia article.  It seems to me that, at the very least, the subject of this article fails to meet Wikipedia's notability guidelines and 100% of the content of the article cannot be verified.  For now, I've added disputed and notability templates to the article.  Should it be deleted?  Marbletan (talk) 14:26, 8 March 2023 (UTC)
 * Yes, I think a PROD is warranted in this case. --Project Osprey (talk) 15:25, 8 March 2023 (UTC)
 * That article was created by User:WhatamIdoing who is still very prolific (and competent). They might like to comment, although IMO the end result will be a deletion. Mike Turnbull (talk) 16:55, 8 March 2023 (UTC)
 * I have no memory of creating this, and no particular attachment to it. Yilloslime made a correction early on, is also still active, and probably knows more about chemicals than I do.
 * I think the biggest challenge in re-constructing this was that another editor blanked the original sources. You can see one of them at https://web.archive.org/web/20071015022448/http://www.montereyherald.com/ci_7145319 (the others don't seem to have been archived), but this source gives the chemical name "polymethylene polyphenyl isocyanate".  Could those be the same thing, just one using a different/outdated naming convention?  (I would have copied and pasted the chemical name from a source [to avoid typos], so it must have been in at least one of the cited sources at the time.) WhatamIdoing (talk) 05:41, 9 March 2023 (UTC)
 * Based on this comment and on Project Osprey's first comment above, I'm now confident that the article content is specific to polymethylene polyphenyl isocyanate and that one of the original sources referred to it as polypropylene polybenzyl isocyanate, either as a typo or misnomer, and that name got carried into the title of the Wikipedia article. Unless there is any objection, I will rename the article polymethylene polyphenyl isocyanate, remove the current useless references, restore WhatamIdoing's original sources, and try to find additional content/sources to improve the article.  Marbletan (talk) 15:17, 9 March 2023 (UTC)

Joseph DeRisi Career draft request
Hey there! I'm trying to improve the biochemist Joseph DeRisi's Wikipedia page, and thought the WP Chemistry Talk page might be a good place to find interested editors. A colleague of mine has composed a new Career draft for the DeRisi page that revises parts of the current Career section for readability, adds new information about Dr. DeRisi's professional life, and removes a few less-than-encyclopedic details. There's currently an open edit request on the DeRisi Talk page asking editors to review that section draft. I'll put a link to the full draft here, as well.

In the interest of transparency: I'm a COI editor working on behalf of Chan Zuckerberg Biohub. Dr. DeRisi is president of CZ Biohub SF. My full COI disclosure is on my user page. If anyone wants to review this Career draft, I'd be immensely grateful for the help. Thank you! K at CZ Biohub (talk) 19:55, 15 March 2023 (UTC)

Antioxidant could use extra eyes
Antioxidant gets about 740 views per day, which is high for us. In this article, the public directly interacts with a lot of chemistry. The article is ok (former FA), but it would benefit from additional curation. The topic susceptible to fringe science. Another problem is that many compounds have some sort of antioxidant activity, of course. Lastly and one of my pet peeves, the article is loaded with primary refs vs refs to books and reviews. If you see issues, please leave a note here or on Talk:Antioxidant. --Smokefoot (talk) 17:03, 17 March 2023 (UTC)


 * I should help here, as this is an area I'm close to professionally, but I've been pushed for time recently. This recent review may prove helpful. Project Osprey (talk) 17:11, 17 March 2023 (UTC)

Project-independent quality assessments
Quality assessments are used by Wikipedia editors to rate the quality of articles in terms of completeness, organization, prose quality, sourcing, etc. Most wikiprojects follow the general guidelines at Content assessment, but some have specialized assessment guidelines. A recent Village pump proposal was approved and has been implemented to add a class parameter to WikiProject banner shell, which can display a general quality assessment for an article, and to let project banner templates "inherit" this assessment.

No action is required if your wikiproject follows the standard assessment approach. Over time, quality assessments will be migrated up to WikiProject banner shell, and your project banner will automatically "inherit" any changes to the general assessments for the purpose of assigning categories.

However, if your project has decided to "opt out" and follow a non-standard quality assessment approach, all you have to do is modify your wikiproject banner template to pass WPBannerMeta a new custom parameter. If this is done, changes to the general quality assessment will be ignored, and your project-level assessment will be displayed and used to create categories, as at present. Aymatth2 (talk) 13:19, 10 April 2023 (UTC)

New article needs input
Greetings. Aldol reactions was just created. Not sure how this differs from Aldol reaction. Would appreciate some input from the project on the article's talk page.  Onel 5969  TT me 09:37, 21 April 2023 (UTC)


 * There is also relevant discussion at Talk:Aldol reaction, a previously featured article now rated "B". Mike Turnbull (talk) 14:47, 21 April 2023 (UTC)
 * Thanks.  Onel 5969  TT me 18:23, 21 April 2023 (UTC)

Request for comment at alchemical symbol
Okay, I know this is a bit off-topic for this project, and not sure chemists would even care that we cover alchemy accurately, but I'd appreciate comments on the RfC on the talk page, or even for someone here to edit the contested bit (or the whole article, for that matter). We have an edit-warrior insisting that we keep a purported old alchemical symbol despite an absence of RS's. I've trimmed a lot of the cruft from that article, don't know why this bit in particular is a problem other than the two of us clashing elsewhere. (The editor says I'm being "disingenuous" by insisting that magnesium is not the same as magnesia.)

Our article has for years claimed that ⚩ is an alchemical symbol for magnesium. The source was Unicode, from versions 4.1 to 5.2. The identification with magnesium was retracted in Unicode 6. It originally came from the proposal for the symbol by Michael Everson, in L2/03-164 (p. 3), whose sole source was an offhand comment in Carl Liungman (1993) Tanketecken, later released (or revised) in English as Dictionary of Symbols, a lay treatment of symbols in general, not alchemy. The people I spoke to at Unicode couldn't find a record of why they retracted the identification, but they suspect it was due to an objection by someone at the Newton Chymistry Project, which is digitizing Isaac Newton's alchemical manuscripts.

The WP editor has now modified the identity of the symbol to "magnesia (alba), source of later magnesium", still claiming the support of Unicode, as if that were a RS. The changed identification is based on Louis Reutter de Rosemont (1931) Histoire de la pharmacie a travers les ages, where a rather similar-looking symbol (I can't judge if it's a variant of ⚩; it looks like it's got a Mercury cap in it) is identified as "magnesia". (See the chart here:, 8th symbol in the left-hand column.) Not as magnesia alba, which is the magnesium salt, so for all I know it might be the manganese salt or some other mineral that once went by the name of 'magnesia'.

Anyway, comments/edits/rewrites welcome. — kwami (talk) 07:55, 21 April 2023 (UTC)
 * The removal seems correct to me, since the source's claim was later retracted. I cannot comment on the alchemy, though. Double sharp (talk) 09:16, 21 April 2023 (UTC)
 * @Kwamikagami Metallic magnesium was not isolated until 1808 (see that article). However, magnesium oxide, also known as magnesia alba, has been known since antiquity and so, in my opinion, is much more likely to have been what the alchemical symbol meant. Mike Turnbull (talk) 12:55, 21 April 2023 (UTC)
 * Yes, and if we had a RS that the symbol was for magnesia alba, that would be good by me. But we don't. We have what might be a variant or misprinting of the symbol (with what appears to be an 🝁 added to the right stroke) for "magnesia", which could be either a magnesium or a manganese compound (magnesia nigra: Manganese). And AFAICT we do know that there were were alchemical symbols for manganese. If someone can find a RS for the claim, I have no problem keeping it. — kwami (talk) 20:03, 21 April 2023 (UTC)

Isomalt: a mixture?
Hello, I would be grateful if an expert could help me out at Talk:Isomalt The article isomalt is a bit unclear about the exact composition of isomalt. Thanks, AxelBoldt (talk) 22:01, 21 April 2023 (UTC)

Nonmetal: Help with copyediting?
Is there anyone here that could help? The nonmetal article has been to PR twice and partly copy edited by User:Jo-Jo Eumerus and User: John. I listed it at the WikiProject Guild of Copy Editors request page on February 2nd 2023 with so far no takers. After the copy-edit I intend to list it for a sixth FAC nomination. Thank you, Sandbh (talk) 03:50, 9 April 2023 (UTC)
 * I'd like to note some non-copyedit issues; in the "Definition and applicable elements" section for example, why is Steudel 2020 so important as to be mentioned by name? Jo-Jo Eumerus (talk) 10:23, 9 April 2023 (UTC)

Only a half-dozen monographs on nonmetals have been published over the last half-century. Steudel 2020 is the 2nd edition of a work first published in 1977. My general presumption is that after 43 years between editions Steudel 2020 is probably a good starting point. Sandbh (talk) 12:39, 9 April 2023 (UTC)
 * Steudel's book is on Main Group Chemistry, which seems in academic circles to be a more common subdivision of inorganic chemistry. Also if one looks at awards, those also are for Main Group, not Nonmetal Chemistry.  There is also a journal on Main Group Chem.  Nonmetal is sort of an older classification based on conductivity of the elements. So one approach would be to shift most content to Main Group Chemistry, and leave a short article on Nonmetals. IMHO--Smokefoot (talk) 13:32, 9 April 2023 (UTC)

Steudel's book is called, Chemistry of the Non-metals: Syntheses - Structures - Bonding - Applications. Nothing specific about main group elements. The first paragraph of the preface is:


 * "How would our planet Earth look like without nonmetals? No water, no air, no life! Not even rocks and sand since oxygen and silicon are responsible for 72.7% of the mass of crustal rocks on the Earth. The human body consists of 96.6% of oxygen, carbon, hydrogen and nitrogen. If all the other nonmetallic elements are added, we end up with 98.0%. Nonmetal compounds play a crucial role in our daily life and in industry as you will see in this book. It is therefore obvious that the chemistry of the nonmetals is a major part of the chemical education at all levels, from high school to university."

Conductivity of the elements has never worked well given carbon is a metallic conductor in the direction of its planes (better than some metals) and arsenic and antimony are metallic conductors.

The earliest attempt I found for distinguishing between metals and nonmetals dates from 1811 and was based on fusibility, malleability, and ductility. Further attempts were based on opacity 1821; cation formation 1911; the Goldhammer-Herzfeld criterion for metallization 1927; bulk coordination number 1949; acid-base character of oxides 1956; minimum excitation potential 1956; sonorousness 1962; physical state 1966; sulfate formation 1966; critical temperature 1973; oxide solubility in acid 1977; enthalpy of vaporization 1986; liquid range 1991; temperature coefficient of resistivity 1999. The latter is unsatisfactory as it results in plutonium being counted as a nonmetal (which it most certainly is not) since it increases its electrical conductivity when heated in the temperature range of around –175 to +125 °C.

The distinction between metals and nonmetals is a classic feature of many periodic tables (the periodic table being an icon of chemistry, and science) by way of the zig-zag line attempting to delineate between the two great classes. Sandbh (talk) 05:51, 10 April 2023 (UTC)


 * The zig-zag line "between" elements more commonly appears as a separate, third major class: metalloids. In the reply here, and in the nonmetal article, by the same editor, this classification feature is ignored (not addressed). Also wrt classification, the article heavily poses new, uncommon and ad-hoc subclassification ("being intermediate between metals and nonmetals", "nonmetal halogens"). So apart from copy edit needs, the issue of undue weight & doubtful classification is entrenched. DePiep (talk) 11:46, 10 April 2023 (UTC)
 * OK, youre right about Steudels book title. But I am correct about Main Group Chem in awards and journals.   The recent ACS National meeting in Indy "Search Results: 3941 results for 'main group'." "Search Results: 6 results for 'nonmetal'."  So the vote is pretty clear at least on this side of the pond.  Nonmetal a fuddy duddy term used by nonchemists (and in the case of Ralf Steudel, deceased chemists).--Smokefoot (talk) 13:15, 10 April 2023 (UTC)

DePiep: Examining the periodic tables shown in 67 chemistry books immediately at hand to me gave the following result:

So, roughly 70% of the time there is no dividing line or a dividing line only.

In the other 30% of cases the metalloids are shown.

Rather than being "more commonly" shown, the metalloids are sometimes shown either in conjunction with the dividing line or by themselves.

Re the article ignoring metalloids, it says, in part:
 * "On a standard periodic table, they [the metalloids] occupy a diagonal area in the p-block extending from boron at the upper left to tellurium at lower right, along the dividing line between metals and nonmetals shown on some tables."

The term "metalloid" appears 49 times.

The phrase, "intermediate class between the metals and the nonmetals" needs to be appreciated in terms of its context within the article, thus:


 * "The elements commonly recognized as metalloids namely boron; silicon and germanium; arsenic and antimony; and tellurium are sometimes counted as an intermediate class between the metals and the nonmetals when the criteria used to distinguish between metals and nonmetals are inconclusive."

For the term "nonmetal halogens" here are some examples from the literature:


 * "In a similar manner the nonmetal halogen elements are arranged."
 * — Essentials of Chemistry - Page 54, Luros G · 1955


 * "The alkali metals of Group la combine readily with the nonmetal halogens of Group VIIa."
 * — General Chemistry - Page 87, John Arrend Timm · 1966


 * "The nonmetallic halogen atoms easily pick up an electron, thus forming halide ions."
 * — Chemistry Decoded - Page 346, Leonard W. Fine · 1976


 * "Iodine is a nonmetallic halogen, having the lowest reactivity of any substance in this group."
 * — Properties of Nonmetallic Fluid Elements - Volume 3, Part 2 - Page 115, Yeram Sarkis Touloukian, ‎Cho Yen Ho · 1981 · ‎p. 115


 * "An activity series for the nonmetallic halogens was given in Chapter 6."
 * — Understanding Chemistry - Page 386, Robert J. Ouellette · 1987


 * "Other properties are similar to those of the nonmetallic halogen elements in Group VIIA or 17 in the second column from the far right of the table…in this case, the nonmetal halogen element is reduced to its halide ion."
 * — Chemistry: A Basic Introduction - Pages 125, 271, George Tyler Miller · 1987


 * "Iodine resembles bromine because they are nonmetallic halogens that form compounds like those of chlorine."
 * — Chemistry - Page 8, Harold D. Nathan · 1993, p. 8


 * "What causes gold to emulate many properties of the nonmetallic halogens?"
 * — Chemical Principles, Page 549, Steven S. Zumdahl · 1995


 * "Particular but we must not forget the novel involvement of the non-metal halogens."
 * — The Chemistry of Evolution: The Development of our Ecosystem, R.J.P Williams, ‎J.J.R Fraústo da Silva · 2005


 * "Among the other nonmetal halogens used to partially halogenate metal oxides…"
 * — Inorganic Reactions and Methods, The Formation of Bonds to…, A. P. Hagen · 2009, p. 221


 * "Non-metallic halogens such as chlorine, iodine and bromine are salt-forming elements."
 * — "TRPM7 is regulated by halides through its kinase domain", H Yu, Z Zhang, A Lis, R Penner, A Fleig - Cellular and molecular life… 2013


 * "Nonmetallic halogen element of atomic number 53…"
 * — Hawley's Condensed Chemical Dictionary - Page 765, Michael D Larrañaga, ‎Richard J. Lewis, Sr., ‎Robert A. Lewis · 2016


 * "Non-metallic halogens are very attractive."
 * — "Hydrothermal preparation of visible-light-driven Br-doped Bi2WO6 photocatalyst", P Dumrongrojthanath, A Phuruangrat, S Thongtem… Materials Letters, 2017 - Elsevier


 * "…chlorine; element #17; a nonmetal halogen gas."
 * — Trauma, 8th Edition - Page 1139, Moore et al. 2017, p. 1139


 * "…and a more detailed grouping in families of: alkali Earth, alkaline Earth, transition metal, rare Earth, other metal, metalloid, and nonmetal halogen to noble gas."
 * — Illustrated Encyclopedia of Applied and Engineering Physics, Robert Splinter · 2017, p. 382

--- Sandbh (talk) 06:19, 12 April 2023 (UTC)
 * Sandbh: Yes the Nonmetal term arises when the Periodic Table is discussed. We need an article on Nonmetal for sure.  It would contain a chart of electrical conductivity of some elements and discuss allotropy.  But the chemistry of the MG elements would be developed in the now short article on MG chem.  Again, thanks for the extensive response.  You are correct that nonmetal is common, if somewhat archaic (fuddy-duddy)  but the MG term rules presently and pretty completely in the academic world.--Smokefoot (talk) 13:28, 12 April 2023 (UTC)
 * I note it to inform or warn interested copyeditors that, apart from copyediting, the article might need structural changes. I don't think this discussion belongs here. DePiep (talk) 06:33, 12 April 2023 (UTC)

Smokefoot: The distinction between metals and nonmetals is a part of Chemistry 101. For example, the Royal Society of Chemistry's English Chemistry Curriculum Map for KS4 (Years 10 and 11) says, "Trends in the periodic table; Explain the reactivity and general properties as related to the atomic structure of groups 1, 7 and 0; between metals and non-metals."

When I search American Chemical Society journals for “metals” I get 287,959 hits; for “non-metals” I get 286,100 hits.

--- Sandbh (talk) 06:19, 12 April 2023 (UTC)
 * Again I assert that a small collection of editors have created a sort of walled garden called Nonmetal, with lots of pictures of minerals (that are off topic). Universities offer courses on Main Group Chem, not on Nonmetal chem.  ACS gives an award for MG Chem, a journal is entitled MG Chem. RSC also has a MG chem section.  Greenwood and Earshaw (the bible of this area): Main Group:52 entries, nonmetal(s/ic): 6 entries.  My guess is that the supporters of this article's title do not interact with contemporary inorganic chemistry. In other words, the title has been hijacked by some hobbyists, not professionals.  In the end, it doesnt matter I guess. Thanks for taking the time to respond.--Smokefoot (talk) 13:10, 12 April 2023 (UTC)

Smokefoot: Thanks for the entertaining assertions. Responding to your earlier post, electrical conductivity figures are given in the Comparison section. Allotropy is discussed in the Allotropes section. "Main group chemistry" returns 343,000 hits on ACS Journals cf. ~287,000 each for "metals" and "nonmetals". That MGC is ~20% more popular than either "metal" or "nonmetal" does not strike me as being particularly significant.

The assertion that there are "lots of pictures of minerals (that are off topic)" does not withstand scrutiny. The article has 12 pictures of nonmetals; in addition there is a picture of a cluster of purple fluorite, a fluorine mineral; and another picture of arsenic sulfide mineral As4S4. The image of fluorite is there as the most common fluoride mineral and main source of fluorine for commercial uses. Arsenic sulfide is composed of two elements each with a predominately nonmetallic chemistry.

According to the electronic version of Greenwood & Earnshaw 2ed, "main group" is mentioned 58 times and "nonmetal(s/ic)" 62 times.

A Google Ngram search for "main group chemistry" and "nonmetals" shows that "nonmetals" appears 90 times more frequently than "main group chemistry" in the English corpus.

Between (i) ACS Journals; (ii) the Royal Society of Chemistry's education curriculum; (iii) G&E; and (iv) Ngram, nonmetals are alive and well and far from having fuddy-duddy status.

In passing, I note that 2019 calculations suggest that copernicium (in the d-block) has a large band gap of 6.4 ± 0.2 eV, which should be similar to that of the noble gas radon (predicted as 7.1 eV) and would make it an insulator; bulk copernicium is predicted by these calculations to be bound mostly by dispersion forces, like the noble gases. If confirmed this would represent the first example of a non-main-group nonmetal.

--- Sandbh (talk) 07:33, 14 April 2023 (UTC)


 * Not helpful to expand & extend your OP here this way. deviation, offtopic, multiforum, possible repetition/incompleteness. btw, entertaining assertions is dismissive. DePiep (talk) 09:04, 14 April 2023 (UTC)
 * OK, my efforts failed. I would be interested in reading your publications and hearing your lectures one of these days.  --Smokefoot (talk) 14:27, 14 April 2023 (UTC)

Thanks very much Smokefoot. Your input was an important contribution. To the extent that we disagreed my view is fairly well captured in this quote:


 * "Disagreements can be unpleasant, even offensive, but they are vital to human reason. Without them we remain in the dark."

TLDR: Truth wins out only after an exchange of arguments. The answers that emerge will be stronger for having been forged in the crucible of our disagreement.
 * The genesis of manned flight, by the Wright Brothers, arose out of disagreement. By allowing their arguments to run hot, the Wrights were able to beat all the experts in the world.
 * The idea that people with different views can vigorously yet co­operatively disagree is essential to democratic society.
 * A good scrap can turn our cognitive flaws into collective virtues.

That is very gracious of you to express an interest in my publications. A list of them is here. The closest I came to a lecture was the virtual presentation I gave to the ACS Spring Technical Program, in 2022. --- Sandbh (talk) 08:03, 15 April 2023 (UTC)

My general impression is that the metal vs. nonmetal (possibly with or without metalloids/semimetals) distinction is generally used by: Personally, I'd rather leave the term to condensed-matter physicists, for whom it is actually useful. Proving my point, the IUPAC Gold Book only defines things like "metal-nonmetal transition" in the condensed-matter-physics meanings. But I guess students are likely to look it up because they see it in textbooks. I agree with 's solution of noting that this is basically a historical and chemical-education term (those fields naturally overlap) with no clear definition and that in modern inorganic research one simply speaks of main-group elements without worrying too much where to draw the lines in a continuous landscape. I'd add that condensed-matter physicists have picked it up with a meaning useful to them, though. Double sharp (talk) 07:35, 16 April 2023 (UTC)
 * 1) Those teaching school-level chemistry, where it becomes a proxy for electronegativity, conductivity, and many other properties. Often it is not exactly and rigorously stated what the defining properties are (nobody agrees on that anyway). This sort of works at that level when you only deal with obvious things like alkali metals and halogens, but is a bit too naïve once you go any further, because once you get outside the most extreme cases, the properties school-level chemistry tells you are stereotypically metallic don't tend to occur together. (Tungsten conducts well and is very dense but tends to form polyoxometallates in solution; meanwhile germanium has some cationic chemistry but is only a semiconductor.) Moreover, properties tend to change continuously down a group: the structures of bulk P, As, Sb, and Bi are as good an example as any, and there's no very natural place to make the cut. (One could start an unproductive myriad-word argument about that but that in itself proves the continuity. As does the fact that it is partly a matter of tradition as opposed to actual clear chemical differences: Russian-language school texts will generally call Sb a metal, while English-language ones generally will not.) In consequence you will still find it in school textbooks and the chemical education literature (e.g. Sandbh's linked paper), but modern researchers will tend to handle things group-by-group, which is more pragmatic given the continuities. Since chemical education generally matches older views of a topic (partly for good pedagogical reasons in which the way you learn something mimicks the way humanity as a whole has been learning it, and partly because no one got the memo from current research) it is natural that older books will talk more about metals vs nonmetals than newer ones do, though even those older books sometimes equivocate on which elements are which (I know one that calls antimony a metal and a nonmetal on two different pages). Sandbh's list of nonmetal monographs itself already proves that metal vs nonmetal is something that was already going out of style as the main division by the 1970s.
 * 2) Those doing condensed-matter physics, where it is purely a one-property thing about conductivity, and so is not really a way of classifying elements but substances (under such schemes, for example, grey arsenic is a metal while black and yellow arsenic aren't).
 * 3) People naming superheavies (which was only an issue for 117 and 118 in the halogen and noble gas groups), which is basically just briefly resurrecting the old classification so that the names don't look out of place, and not really using it in practice. Besides, the average inorganicker does not care about superheavies.


 * Thanks Double sharp for your interesting thoughts.


 * There is no reliable evidence, that I know of, to sustain a suggestion that, "metal vs nonmetal is something that was already going out of style as the main division by the 1970s."


 * The ACS and RSC both have periodic tables that feature a distinction between metals and nonmetals. The ACS periodic table is further included on the back of their membership cards. The RSC table is especially interesting since it counts the metalloids as nonmetals, rightly so since metalloids have predominately nonmetallic chemistries. Less notably, the Encyclopedia Britannica periodic table maintains a metal-nonmetal dividing line.
 * --- Sandbh (talk) 04:38, 23 April 2023 (UTC)
 * The list of nonmetal monographs you linked to contains only three entries after the 1970s. And one of them is simply an updated version of one of those 1970s books. I do not dispute that the metal vs. nonmetal division continues to be used. I simply note that this looks like good evidence that it's not the main division used by practicing chemists. Stuff used on decorative periodic tables is something different and is closer to my #1. Incidentally, you are not telling the full story: the RSC table counts the metalloids as both metals and nonmetals. As for "predominately nonmetallic" chemistries, note that by any reasonable definition At has more of that than Sb does (after all, astatine will form simple anions), yet relativistic calculations suggest that At is a metal in the physicist's sense and Sb is only a semimetal. Of course, in spite of this, it would be pretty eccentric to discuss astatine with anything but the halogens. Again, that shows that the mass of vaguely correlated properties that school texts will tend to identify as pinpointing nonmetallic character do not actually have that simple a relationship with each other. This perhaps sheds some light on why chemists tend to consider things group-by-group today instead of futilely debate on where to draw lines, and why physicists have specialised the metal vs. nonmetal classification to just conductivity. Double sharp (talk) 21:51, 23 April 2023 (UTC)

If there is so much disagreement about the article topic, an idea I would pursue is to a) assemble all the most commonly cited textbooks or other overarching sources on chemistry and b) draft a new article text that discusses (compares) the various definitions of "nonmetal". Jo-Jo Eumerus (talk) 08:25, 23 April 2023 (UTC)


 * By this thread, the claim is that "main group" and "metal-metalloid-nonmetal" chemistry/physics are different topics and so to be handled in two different articles. This is not about the concept of "metal" evolving (changing) into "main group". BTW, both articles exist. DePiep (talk) 10:49, 23 April 2023 (UTC)
 * I agree. They are different classifications. One has overtaken the other in the literature, but they are not synonymous. Double sharp (talk) 21:51, 23 April 2023 (UTC)

Thanks

The assertion that, "one of them is simply an updated version of one of these 1970s books" is not supported by the following comments in the preface to Steudel (2020):


 * Nonmetal compounds play a crucial role in our daily life and in industry as you will see in this book. It is therefore obvious that the chemistry of the nonmetals is a major part of the chemical education at all levels, from high school to university.


 * The book you are holding in your hands is very special to me. I wrote the first German edition at the very early stage of my academic career...It originated from my lectures at the Technical University Berlin, the place known as a hotspot of nonmetal chemistry research. With the years, the book became my lifetime project. I was fortunate enough to share my passion and interest in the chemistry of the nonmetals (and the yellow element in particular) with many friends and colleagues in academia and industry all over the world. Thus, the book was always nourished with the modern developments in fundamental and industrial research.


 * Five editions of this monograph have been published by de Gruyter, Berlin/Boston, each time completely modernized and extended. This newest international edition is an updated translation of the latest German edition of 2013. I am grateful to my two younger colleagues who share the same passion...


 * Numerous review articles and original publications are cited in footnotes and encourage the readers to study certain topics more extensively. To keep the size of the footnotes with nearly 1000 references under control, however, only one author is given if there are more than three.


 * Literature closing date was spring 2019.


 * De Gruyter Publisher in Berlin supported this project from day 1, so that many people who worked with me all these years should be acknowledged.


 * Many colleagues, coworkers and students contributed to the success of this book with their comments and suggestions and I will be happy to hear from the readers of this edition too

My comment about the RSC's treatment of metalloids was wrong. Thanks for pointing that out.

I agree about At. While it could reasonably be presumed to be a metalloid based on ordinary periodic trends, relativistic effects—as seen in gold, mercury, and the heavier p-block elements—are expected to result in condensed astatine being a ductile metal. Astatine could also be expected to show significant nonmetallic character, as is normally the case for metals in, or in the vicinity of, the p-block.

Regarding futilely debating where to draw lines, chemistry has all sorts of fuzzy definitions and the article accommodates and acknowledges a divergence of views.

The physicists' metal vs. nonmetal classification on the basis of electrical conductivity probably works for them as a simple generalisation but does not accommodate the view that chemistry is not reducible to physics. It potentially causes some difficulties elsewhere as it results in carbon and arsenic being counted as metals.

Thanks There is no substantive disagreement about nonmetals in chemistry beyond the par-for-the-course fuziness at the edges. The article surveys the varying suggested definitions of a nonmetal in the suggested distinguishing criteria section. --- Sandbh (talk) 04:45, 24 April 2023 (UTC)
 * You yourself said at the beginning of this thread that Steudel 2020 is the 2nd edition of a work first published in 1977. And Steudel himself, according to your quote, admits that this is a modernized and extended version of a book he first wrote at the very early stage of [his] academic career. It amazes me that you quote all of this and then claim that my assertion that this "is simply an updated version of one of these 1970s books" is not supported. Double sharp (talk) 18:49, 24 April 2023 (UTC)

Well, yes, Steudel 2020 is the 2nd (English/international) edition of a work first published in 1977. I added, My general presumption is that after 43 years between editions Steudel 2020 is probably a good starting point. Until I read your assessment of Steudel 2020 as simply an updated version of one of these 1970s books it had not occurred to me to read the preface. Upon which I learnt that Steudel 2020 is an updated translation of the 5th German edition of 2013, incorporating the literature up to Spring 2019. That seems clear enough to me. --- Sandbh (talk) 00:10, 25 April 2023 (UTC)
 * An update of an update is still an update. Double sharp (talk) 21:22, 27 April 2023 (UTC)

Covalent compounds and naming
Hello. There are at least 13 articles on compounds that are not ionic (e. g. technetium hexafluoride, ruthenium hexafluoride, rhodium hexafluoride, tungsten hexafluoride, rhenium hexafluoride, osmium hexafluoride, iridium hexafluoride, platinum hexafluoride, ruthenium pentafluoride, vanadium pentafluoride and even xenon difluoride, xenon trioxide and xenon tetroxide) but according to the articles, they have an official name containing the oxidation number in Roman numerals.

Also, there are at least 2 articles (not redirects!) about non-ionic compounds not using the correct name as their title (e. g. iridium(V) fluoride and rhenium(VII) oxide).

Or am I using the rules of chemical nomenclature wrong? Alfa-ketosav (talk) 16:26, 25 April 2023 (UTC)
 * There isn't such a rule. Stock nomenclature is correct even for obvious covalent compounds. We just tend to avoid it then because in those cases it is usually not the most common name. Besides, it is impossible to clearly define the boundary between covalent and ionic, since that is a continuum (and forgets about cases like IrO2 which has metallic conductivity). We already have exceptions like mercury(II) chloride (which is, despite the low oxidation state, molecular). Double sharp (talk) 21:25, 27 April 2023 (UTC)

Ethidene dichloride
Afternoon folks!! I notice there isn't an article or redirect on this substance, which was used as an artificial Anaesthetic around the 1860-1890's. I wonder if its interesting enough for somebody to do an article. I don't know if there is an article already, not being a chemist. Would it be this 1,1-Dichloroethane? A google search seems to point to this but I'm not sure. Thanks.  scope_creep Talk  11:24, 28 April 2023 (UTC)
 * A Google search and a working knowledge of chemical nomenclature leads me to the same conclusion as you: ethidene dichloride is 1,1-dichloroethane.  "Ethidene dichloride" is archaic nomenclature, so it's hard to be 100% sure though.  It's also possible that the actual product was an ill-defined mixture of closely related chemical compounds (which might include 1,2-dichloroethane, dichloroethenes, etc. in addition to 1,1-dichloroethane). Marbletan (talk) 14:36, 28 April 2023 (UTC)
 * @Scope creep This Google book entry from 1884 has lots of hits for ethidene dichloride which confirm it is 1,1-dichloroethane. Mike Turnbull (talk) 20:02, 28 April 2023 (UTC)

Requested move at Talk:Aldol reaction
There is a requested move discussion at Talk:Aldol reaction that may be of interest to members of this WikiProject. SkyWarrior 22:11, 28 April 2023 (UTC)

Talk:Fire

 * seeking input. Also, Fire has been semi-prot for 13 years. Any feelings on whether it should be unprotected? --47.155.41.201 (talk) 04:18, 29 April 2023 (UTC)


 * This issue has been resolved, and did not require canvassing this WikiProject because it was so minor. I have filed an unprotection request at WP:RFPP, citing this discussion. –LaundryPizza03 ( d c̄ ) 06:57, 29 April 2023 (UTC)
 * Said unprotection request has been declined, sorry. 162.219.198.189 (talk) 21:26, 29 April 2023 (UTC)

Separation process & List of purification methods in chemistry, merge/split? I think we should merge them.
Title.

捍粵者 (talk) 15:23, 30 April 2023 (UTC)

FAC Nomination: Nonmetal (chemistry)
Please see here.

thank you, Sandbh (talk) 12:39, 2 May 2023 (UTC)

Samarium at FAC
Featured article candidates

— Sandbh (talk) 11:09, 7 May 2023 (UTC)

Missing article: Poly-viscose
Please see: Wikipedia talk:WikiProject Textile Arts. — SMcCandlish ☏ ¢ 😼  02:11, 31 May 2023 (UTC)

RfC re periodic table
Editors interested in the categories and colors of the periodic table are invited to participate in a discussion at. YBG (talk) 14:14, 24 May 2023 (UTC)


 * The discussion about a periodic table with no colours was unanimously opposed and has been closed.

Discussion remains open on:
 * Side discussion re venue
 * Scary ambiguity?
 * Black and white labelled PT (noting not all elements are shown as the same colour).

--- Sandbh (talk) 07:51, 31 May 2023 (UTC)