Talk:rhodammonium

RFV discussion: June–July 2023

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rhodammonium

I don't think this is an adjective No hago griego (talk) 21:29, 16 June 2023 (UTC)

Fixed. This seems to be easily verifiable, but:

• Virtually all the sources are from the 1800s. This leads to a question: is the term "obsolete" (this particular ion is still in use but has a different name) or "historical" (this ion is no longer relevant to modern science)? Possibly both are true.
• Roscoe describes the compound as having a ratio of 2 rhodium to 10 ammonia. However, most of the information I can find on rhodium complexes suggests that Rh binds with 6 ligands - for example, the complex known by the modern systematic name hexaamminerhodium. Perhaps the referent of the term is any rhodium-ammonium complex. Compare w:Template:Rhodium compounds.

What a mystery! Do we have specialist chemistry editors? I may look like I know what I'm talking about, but I really don't... This, that and the other (talk) 11:25, 17 June 2023 (UTC)

Graeme Bartlett? * Pppery * _{it has begun...} 23:31, 17 June 2023 (UTC)

The original entry (from Webster 1913) was more adjectivally written, but that might not say much. Alas, our resident chemist SemperBlotto ain't around any more. Equinox ◑ 23:50, 17 June 2023 (UTC)

I am not a chemist, but I dug up and added some quotes, and looking at the formulas for rhodammonium compounds, this looks right to me. Kiwima (talk) 04:52, 18 June 2023 (UTC)

As to whether it's 'obsolete' or 'historical': assuming it's a real ion, IMO it could only be obsolete (if the word is no longer used), but not historical, because it's not as if an ion stops existing in the universe (over the timescale we're talking about here). I'm not even convinced we should be labelling e.g. vambrace or couter historical — and we don't label greave or breastplate or sword that way — because people still make, buy / sell, and use them, even though now only for recreational fighting and not warfare. - -sche (discuss) 07:05, 18 June 2023 (UTC)

It would be nice if we could offer users a term currently used for the same referent.

Our methods only allow us to determine whether a word is still in visible use, not the concept and still less the referent. I hope our users get that. We confuse the issue by our failure to distinguish topic and usage context in our labels. DCDuring (talk) 14:57, 18 June 2023 (UTC)

Good point, @-sche - the ion itself wouldn't disappear into non-existence. However, the term could plausibly be marked (historical) if the ion was found not to actually exist, no? Compare phlogiston. This, that and the other (talk) 01:13, 19 June 2023 (UTC)

If a term is still used e.g. when discussing the history of people's ideas about X, but the thing is not still used, then yes, "historical", and then if the thing was only conjectured to exist but doesn't actually exist, I would expect the definition to clarify that like phlogiston does. If (as seems to be the case here) the term is no longer used, I'd expect "obsolete" regardless of whether the thing itself still exists under another name or doesn't still exist (and I would again expect information about whether it ever existed to be in the definition). In this case, I don't see a reason offhand to think Rh₂(NH₃)₁₀⁶⁺ couldn't exist, at least as part of larger compounds like some of the cites are talking about (other Rh₂(NH₃)_N compounds get mentioned in chemistry texts), but I am no chemist and perhaps it is indeed ruled out. Perhaps we can sidestep that, because looking at the cites, I get the sneaking suspicion, like Pppery, that this in fact refers to rhodium-ammonium more generally. BTW, checking various disused-concept entries I find they are not consistent and may need cleanup, e.g. luminiferous aether has an "obsolete" that looks like it should be "historical" and miasma has no label at all... (Do we categorize "obsolete concepts" like those anywhere?) - -sche (discuss) 14:04, 19 June 2023 (UTC)

The cites are "rhodammonium compounds" contrasted with "cobalt- and chrom-ammonium compounds", "Rhodammonium Hydroxide" and "rhodammonium chloride" contrasted with e.g. "silver oxide", "ammonium chloride and [...] rhodammonium trichloride", "rhodammonium or [...] potassium dichromate and ammonium sulphate". Should we generalize slightly to "A cation or compound containing rhodium and ammonia." or leave it as-is? - -sche (discuss) 13:36, 23 June 2023 (UTC)

@-sche: The "obsolete" label for "luminiferous aether" is just wrong—the term is still widely used and understood—and I've corrected it. Obsolete vs. historical have very distinct meanings IMO and I agree they should just be cleaned up if they're being used incorrectly. Sometimes both might apply to stuff like this, though in any case the criterion for treating a term as "obsolete" is that it won't be understood (even in a specialist context) when used, which seems to be the case here. —Al-Muqanna المقنع (talk) 12:12, 17 July 2023 (UTC)

Checking Google scholar, it has not been used for over a century in English writings. So marking it as obsolete, as it is now, is the right way to go. Also it is one of those nouns like ammonium, just about always used in combination. I think this RFV can be closed, as everything looks good about the entry. Note it is also German for the same thing. Graeme Bartlett (talk) 03:18, 19 June 2023 (UTC)

RFV-passed. —Al-Muqanna المقنع (talk) 12:12, 17 July 2023 (UTC)