Talk:Iridium disulfide

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—Syrenka V (talk) 13:31, 19 January 2019 (UTC)

Oxidation state and page naming

I have undone the renaming of the page from "Iridium(IV) sulfide" to "Iridium disulfide". The WebElements reference, although it uses the name "Iridium disulphide" itself, not only gives "iridium(IV) sulfide" as a legitimate synonym, but explicitly states that the oxidation state of iridium in this compound is +4.

Please discuss this matter further on this page before any further page moves.

—Syrenka V (talk) 14:12, 19 January 2019 (UTC)

Having discussed the matter further (see next section), I'm convinced that the original page move was correct, and I've moved the page back to Iridium disulfide. The consensus process at work...

—Syrenka V (talk) 15:02, 19 January 2019 (UTC)

Ir(IV)

Oh, we are smarter than that website, which is a shitty source. No way its Ir(IV), but you need to know the chemistry of metal sulfides. See, the sulfur is persulfide-like. Just like FeS2 (either polymorph). I can explain more if you want.--Smokefoot (talk) 14:23, 19 January 2019 (UTC)

Please do explain (and see below about WebElements and its author). It is true that I am not myself a chemist. The Munson 1968 source does say that some of the iridium is likely in a +3 oxidation state, and gives fractional oxidation statessubscripts that must be averages among heterogeneous subpopulations of atoms in different oxidation states.

By your reference to persulfides, I take it that the sulfur has some S–S bonds, like the O–O bonds in a peroxide, so that some of the sulfur has an oxidation state of –1 (or even closer to 0 if the chains are longer than two atoms), so that some of the iridium can likewise have a (positive) oxidation state that is closer to 0.

I now see that the article on Pyrite explains the above, and gives an oxidation state of +2 rather than +4 for the iron in ${\ce {FeS2}}$. So it looks as though you are right. But if so, please find some sources to cite for the above, and put it in the article—not just in the name.

—Syrenka V (talk) 14:37, 19 January 2019 (UTC)

Another point: the Munson article's fractional subscripts indicate that the picture may be more complex than with pyrite on the one hand, or with ${\ce {MoS2}}$ on the other (cited in the Pyrite article as an example of a case where the metal truly is in a +4 oxidation state). Some of the iridium atoms might be +3, for example.

In any case, whatever Winter's level of expertise or reliability in general, just from looking over Munson 1968 and thinking over the above points, it appears you are right about renaming the page, and WebElements is wrong, so in retrospect you were right to rename the page, and you have consensus for changing it back to Iridium disulfide.

—Syrenka V (talk) 14:50, 19 January 2019 (UTC)

These materials are highly covalent, as reflected by their semiconducting properties. So crisp oxidation state definitions dont work. For this reason, assignments of oxidation states are avoided. Ir(II) is implied by S₂^2- but is an overstatement as you indicate above. Correspondingly Ir(IV) implies isolated S^2-.

Peroxides are less covalent, so the ionic model applies well. They are insulators. Going in the other direction, oxidation states for metal diselenides and ditellurides are more ambiguous. --Smokefoot (talk) 14:59, 19 January 2019 (UTC)

WebElements as a source

The WebElements page should not have been removed as a source, certainly not without first finding a better source for the same information. Note that although WebElements is self-published, its author, Mark Winter, is a published expert on chemistry (specifically, a chemistry professor at the University of Sheffield). See his page there. Although self-published sources are never ideal, WP:SELFPUBLISH within WP:V allows their use when the author is a recognized expert with a record of third-party publications in the relevant field. Prof. Winter meets this criterion.

—Syrenka V (talk) 14:25, 19 January 2019 (UTC)

Dont assume that your fellow editors are less distinguished that Winter who manages a website. --Smokefoot (talk) 14:28, 19 January 2019 (UTC)

No personal offense was intended. I was purely discussing WebElements and Winter as sources, not making any sort of comparison between his expertise and that of any editor. If you are also a chemistry professor with published works to cite (be they self-published or peer-reviewed), by all means do so.

—Syrenka V (talk) 14:43, 19 January 2019 (UTC)

No offense taken. Wiki-chem is supported by a strong team editors, and we often express some disdain for other websites, in part because other sites are not well curated.--Smokefoot (talk) 14:59, 19 January 2019 (UTC)