Talk:helionium

helionium sense

 * I think that sense 2 (an antiproton and a helion) should be deleted. The onium should only apply to a helion and an antihelion.  An antiproton and a helion would be antiprotonic helium-3 and an antihelion with a proton would be protonic antihelium-3.  The onium is a special case since the masses of the particles are identical so that there is no equivalent to a conventional atomic nucleus.  Nicole Sharp (talk) 04:05, 29 December 2021 (UTC)
 * But see also: " ." Nicole Sharp (talk) 04:10, 29 December 2021 (UTC)


 * There is a discussion open at WT:RFV at Requests_for_verification/English discussing this page. Sense 2 (antiprotonic helium) has been discovered with sources at that discussion. It was also indicated at wikipedia:en:Talk:Helionium -- 65.92.246.142 16:49, 29 December 2021 (UTC)

RFV discussion: December 2021–January 2022
One English BGC result, few promising ghits. &mdash; S URJECTION / T / C / L / 18:41, 28 December 2021 (UTC)

I have added two citations to the citations page. I think I found more, but they are behind a paywall. I do question whether the two definitions refer to different things: it looks to me like two ways of describing the same thing. Kiwima (talk) 19:44, 28 December 2021 (UTC)


 * I reached behind the paywall and added the third cite, so it's now cited. This is certainly a rare term though!
 * It's fascinating that the 1981 paper doesn't give even the briefest definition or explanation of helionium, which makes me believe there is an earlier source out there somewhere, perhaps not digitised. This, that and the other (talk) 00:23, 29 December 2021 (UTC)
 * Hmm, I just realised this is more messy than it looks. The word is being used in several different ways:
 * The 1981 article uses helionium to refer to a combination of a helion with an antiproton.
 * The 1985 article is referring directly to the 1981 article. The sentence right before the one on the citations page is "These effects have been calculated for light antiprotonic atoms by Barmo et a1 (1981)."
 * The 2013 book says helionium is a combination of a 4He nucleus (which has 12 quarks, compared to a helion with 9 quarks) with an antiproton. This is obvious from Figure 33.
 * Our sense 1 says it is a combination of a helion with an antihelion.
 * Our sense 2 says it is a combination of a helion and two antiprotons (because a helium atom normally has two electrons).
 * So we are going to have a bit of trouble defining the term. This, that and the other (talk) 00:46, 29 December 2021 (UTC)
 * For a formal prescriptivist (instead of descriptivist) definition, I would not trust usage citations that do not come from peer-reviewed journals in chemistry, nuclear physics, particle physics, or astrophysics. Nicole Sharp (talk) 19:07, 29 December 2021 (UTC)
 * We only do descriptivist definitions here, although we can be mildly prescriptive in the usage notes if it is of assistance to the reader. The 1981 and 1985 cites are certainly peer-reviewed and I suspect the 2013 one is as well. This, that and the other (talk) 00:40, 30 December 2021 (UTC)

Helionium would be more formally referred to as antihelionic helium-3 or helionic antihelium-3 (which are identical states). Antiprotonic helium-3 though could also be referred to as antiprotonic helionium, since helionium and helium-3 both have helions for nuclei. From a prescriptivist perspective on the correct usage of "onium," this is likely the source of the confusion. Additional confusion can also be created by referring to a bound state of an alpha particle and anti-alpha particle (which could be called "alphonium") as "helionium" despite not containing any helions, since it is also a "helium-onium" without clarification between the terms "helion" and "helium" when suffixed with "-onium." Nicole Sharp (talk) 19:17, 29 December 2021 (UTC)

The most general sense of "helionium" would be from the etymology of "helium-onium" instead of "helion-onium." In this sense, "helionium" would be any atomic system containing a helium nucleus and an antihelium nucleus. So then an atomically bound state of an alpha particle and an antihelion could be referred to as "helionium" but should more properly be referred to as antihelionic helium-4 instead, to avoid confusion. Nicole Sharp (talk) 19:31, 29 December 2021 (UTC)

RFV-resolved. I took 's analysis to merge and rewrite the definitions into something supported by the citations. Kiwima (talk) 00:41, 7 January 2022 (UTC)


 * Most of sources found by This, that and the other indicate it is a helium nucleus (helium-3, helium-4) and (an) antiproton(s) that replaces (an) electron(s), which is different from the onium state of a particle-antiparticle pairing. The current new definition is just the onioum definition and is missing the antiprotonic version. -- 65.92.246.142 17:51, 15 January 2022 (UTC)