Basilicofresco

Drop me a message, I will gladly read it!

---

Chemical compounds

Hey. Thank you for contributing to the chemical part of the Wikidata. While I think most of your edits are good, I had to revert three edits:

• atropine (Q26272): this item is about a racemic mixture, you can't assign a molecular formula or PubChem Compound ID to a mixture; the proper items are (±)-hyoscyamine (Q73418929) – this one is about a group of stereoisomers – and (+)-hyoscyamine (Q27121382) and hyoscyamine (Q413762) – these two are about components of atropine (Q26272).
• bacitracin (Q61954719): this item is about a mixture of peptides and the reason is as above.
• azide (Q407627): this item is about a class of chemical compounds, not about an azide ion; the proper item is azide ion (Q10853389).

Mistakes like the ones above are usually caused by the fact that items in Wikidata and Wikipedia articles are not 100% equivalents. However, Wikipedia sitelinks do not define the Wikidata items, sitelinks are just an addition to the item. You should always check instance of (P31) and subclass of (P279) statements; in some situations different from (P1889) and has part(s) (P527) may be helpful in finding the proper items. Best regards, Wostr (talk) 16:18, 23 July 2020 (UTC)

@Wostr: Thanks. Your help is more than appreciated. Talking about atropine (Q26272) I assumed that since it is a mixture of two enantiomers with the same molecular formula, then the mixture has de facto a molecular formula... is it not considered acceptable in this case? -- Basilicofresco (talk) 17:17, 23 July 2020 (UTC)

While chemical formulae are not reserved for pure chemical compounds (such formulae are used also for adducts, minerals, alloys etc.), it's not clear (at least to me) which chemical formula is correct for a racemic mixture (or any mixture). Let's take atropine (Q26272): is it C₁₇H₂₃NO₃ (the same formula as for each enantiomer), or maybe it should be C₃₄H₄₆N₂O₆ (because theoretically you need at least two enantiomers)? It is technically possible to add chemical formula (P274) to items about mixtures (there is no subject type constraint (Q21503250)), but I'm not sure we should do that, just like we don't use SMILES/InChI in items about racemic mixtures. You may, however, ask about this in Wikidata:WikiProject Chemistry, as this is just my opinion. Wostr (talk) 18:36, 23 July 2020 (UTC)