User talk:Dirac66/Archive 6 (2019-2021)

Term Symbol

user:DePiep redirected that template page with his magic powers [1] and I cannot figure out how to get at it for edits. You might ask him. SBHarris 05:35, 23 January 2019 (UTC)

See my talk page. Double Sharp did some template voodoo and I think I was then able to edit out the problem. SBHarris 07:13, 23 January 2019 (UTC)

Thanks for recruiting someone who knew how to fix it. Now we have the correct term symbols. Dirac66 (talk) 17:51, 23 January 2019 (UTC)

Detecting Hydrogen

Hello Dirac66. I left you a comment in the Rutherford talk page. StevenBKrivit (talk) 04:31, 22 June 2019 (UTC)

Lindemann

Everything in the intro comes directly from the main article. It is those elements that may or may not need additional references. Valetude (talk) 07:56, 9 July 2019 (UTC)

VSEPR

Hi Dirac66. Thanks for your edit in VSEPR. Please see my further edit. Special:Diff/908044486. My understanding is that these two "advanced-level explanation" statements are not part of VSEPR and require attribution/citation. --Taweetham (talk) 02:09, 27 July 2019 (UTC)

@Officer781:

Yes, I agree. I have now checked the edit history of this article, and the mention of the "advanced" explanations of this point dates back to edits by Officer781 in April 2015. So let's ask him if he knows of sources for this material. Dirac66 (talk) 03:05, 28 July 2019 (UTC)

@Dirac66 and Taweetham: It has been a while now and I have forgotten my motivation for adding these claims (let alone the sources for them). I think if you would like to remove them it seems fine by me.--Officer781 (talk) 15:35, 5 August 2019 (UTC)

@Officer781 and Taweetham: I have now deleted the first claim re electronegativity effect as unsourced. I was able to find a source for the second claim re bond order in a textbook already used as a source, so I kept that one, although without the word "advanced". Dirac66 (talk) 22:26, 5 August 2019 (UTC)

Many thanks to @Dirac66 and Officer781:. --Taweetham (talk) 05:27, 7 August 2019 (UTC)

Main topic of interest in physical chemistry

Hi Dirac!

I have noticed your various edits at physical chemistry articles. Therefore I want to ask you what is your main area of interest re this range of topics: spectroscopy, chemical kinetics, chemical thermodynamics or other? Thanks!--109.166.139.190 (talk) 16:54, 26 October 2019 (UTC)

I have taught all of these. Perhaps I find chemical kinetics most interesting, followed by spectroscopy. Dirac66 (talk) 02:37, 27 October 2019 (UTC)

How about electrochemical kinetics? Could it be even more interesting than chemical kinetics?--109.166.139.190 (talk) 14:45, 27 October 2019 (UTC)

Not really to me. But why are you asking? Dirac66 (talk) 19:12, 27 October 2019 (UTC)

I'm asking in a comparative context of the two types of kinetics (to see the aspects that form the degree of their individual interestingness). It seems that the kinetics of reactions involving ionic solutions (and melts) in absence of any electrodes can be included in chemical kinetics, not electrochemical.--109.166.139.149 (talk) 15:53, 6 November 2019 (UTC)

In this context re physical chemistry another question appears re the ratio experiment to theory which forms the next section below.--109.166.139.149 (talk) 16:08, 6 November 2019 (UTC)

Another interesting aspect in this context involves the interactions of these separate branches of physchem, what is the measure of their interaction, kinetics with spectroscopy, kinetics with thermodynamics, thermodynamics with spectroscopy,...etc in your activity of teaching and research?--109.166.139.149 (talk) 16:21, 6 November 2019 (UTC)

Combination of experiment with theory in physical chemistry

The question appeared in the section above is: How do you view the combination experiment to theory in physical chemistry, what is your preference re the ratio of the two aspects in your physical chemistry activities?--109.166.139.149 (talk) 16:15, 6 November 2019 (UTC)

Buffer solution

Buffer capacity, β, is a quantitative measure of the resistance of a buffer solution to pH change on addition of hydroxide ions (OH^–) or of hydronium ions (H₃O⁺). It can be defined as follows. (references removed)

$\beta ={\frac {dC_{b}}{d(p\mathrm {H} )}}$ for addition of base; or $\beta =-{\frac {dC_{a}}{d(p\mathrm {H} )}}$ for addition of acid.

where $dC_{b}$ is an infinitesimal amount of added base, or $dC_{a}$ is an infinitesimal amount of added acid, pH is defined as −log10[H+] and $d(p\mathrm {H} )$ is an infinitesimal change in pH. With the first definition the buffer capacity for addition of base to a weak acid, with dissociation constant Ka, can be expressed as

$\beta =2.303\left([H^{+}]+{\frac {C_{a}K_{a}[H^{+}]}{(K_{a}+[H^{+}])^{2}}}+{\frac {K_{w}}{[H^{+}]}}\right)$

There is nothing scientifically wrong with this text. The reason why it was rejected was because the final expression contains C_a but does not contain C_b, so the reason for including the latter in the text is not explained. It is elementary that the addition of an infinitesimal quantity of H⁺ is equivalent to the removal of the same quantity of OH^-. If you think that it's worth stressing it should be stated separately from the equation. There is no point in showing a second equation with buffer capacity as a function of [OH^-]. Petergans (talk) 10:48, 23 January 2020 (UTC)

I prefer to make clear that buffer capacity is defined both for addition of base and addition of acid, which may not be obvious to all readers. The equivalence of adding acid and removing base does not actually imply equal and opposite changes, because it is the product [H⁺][OH^-] which is constant and not the sum. For example, if we start with an acetic acid-acetate buffer at pH 5 and add enough HCl to bring the pH to 4, then Δ[H⁺] = 10^-4 - 10^-5 = 9 x 10^-5, but Δ[OH^-] = 10^-10 - 10^-9 = -9 x 10^-10. Instead the two definitions of buffer capacity are equivalent in the sense that one is true for addition of acid and the other for addition of base, which I think is not completely obvious and should be specified. Dirac66 (talk) 23:11, 23 January 2020 (UTC)

@Petergans

As for the buffer capacity formula containing C_a and not C_b, I have just realized that our present notation is inconsistent. In the definition β = -dC_a/d(pH), C_a is the concentration of H⁺ added in the form of a strong acid such as HCl, which is consistent with the meaning of C_b and with the sources. However in the 3-term formula for buffer capacity, C_a is instead the analytical concentration of the buffer acid, e.g. acetic acid plus acetate. I will change the symbol for the second meaning to [X]_T as per Urbansky and Schock. Dirac66 (talk) 03:00, 24 January 2020 (UTC)

It's about what happens when the pH changes, not how that change is brought about. Petergans (talk) 17:52, 29 January 2020 (UTC)

Protonation constants

I am working on acid dissociation constant again and this point has come up.

You and others (e.g. Skoog et.al) write [H₃O⁺] for the hydrogen ion concentration in quantitative expressions. In my view this is both misleading as it ignores species such as H₄O₉⁺ and unnecessary as it plays no part in the context of the chemical equations regarding protonation constants. My personal preference would be to relegate the aquation of protons to a footnote. Petergans (talk) 17:40, 29 January 2020 (UTC)

The article Acid dissociation constant only has H₃O⁺ in the Definitions section, which I don't remember editing. I will assume instead that you are referring to the article Buffer solution, where I now note that the only few H₃O⁺ in the article are in my recently added comments on the 3 peaks of the buffer capacity curve. For the sake of consistency with the rest of the article, I will agree to change these to H⁺. However instead of a footnote, I prefer to add a brief explanation in the actual article, to help any readers who may think that H⁺ is a bare proton. There is a good sentence in the article Acid dissociation constant with a link to the article Hydronium ion. I will copy this sentence into the Buffer capacity article. Dirac66 (talk) 03:06, 30 January 2020 (UTC)

Many thanks. The underlying complexities don't belong in this article. For instance, the very first equation could be written in Bronsted-Lowry terms as HA + H₂O = H₃O⁺ + A^-. This has implications for dimensionality, for pH = -log(H₃O⁺) and so on. Such matters are of minimal importance in the context of buffer solutions and how they are used. Petergans (talk) 09:21, 30 January 2020 (UTC)

Please leave the Acadian pages alone

We use the tricolor with the star these days. It is very culturally significant in what is an ongoing cultural conflict (which we're surprised needs to keep being a conflict). Please don't dispute our tricolor. Thank-you! 134.41.125.152 (talk) 03:56, 13 April 2020 (UTC)

Je suggère d'inclure les deux drapeaux dans l'article. Le drapeau acadien moderne a été enlevé de l'article par quelqu'un d'autre (pas moi) le 24 décembre dernier, sous prétexte que l'article s'agit de l'Acadie coloniale. Alors le 3 février j'ai ajouté le drapeau de l'époque coloniale comme alternative. Mais je pense vraiment qu'il serait mieux d'avoir les deux (bien identifiés) afin d'indiquer que l'Acadie existait aux 17e-18e ET existe encore. En plus le texte devrait inclure davantage d'histoire acadienne moderne, comme j'ai déjà dit à la page Discussion de cet article. Dirac66 (talk) 16:28, 13 April 2020 (UTC)

Raman scattering

Thanks for correcting my edit on Raman scattering, I think I misread the part about IR and thought it was all the same process, in any case you've fixed it now. Cheers Polyamorph (talk) 07:07, 25 April 2020 (UTC)

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Coactive nonmetals and halogen nonmetals

G’day Dirac66

I write to gauge your thoughts about a proposal to change the nonmetal categories appearing in our periodic table from {reactive nonmetals} and {noble gases} to {coactive nonmetals} {halogen nonmetals} and {noble gases}

thank you, Sandbh (talk) 07:28, 10 August 2020 (UTC)

*     *     *

Context. There has been some discussion about nonmetal categories at WP:ELEMENTS.

I suspect most active members of that project (including me) would agree to divide the reactive nonmetals i.e. the nonmetals other than the noble gases, into two relatively clear and self-descriptive categories. However, since the WP periodic table was created, we haven't found a good way of doing this.

I caveat the expression "relatively clear" by what we say in our periodic table article:

"Placing elements into categories and subcategories based just on shared properties is imperfect. There is a large disparity of properties within each category with notable overlaps at the boundaries, as is the case with most classification schemes."

That said, didactically speaking, the use of "natural" classes or clusters to organise information supports content processing.

In Wikipedia history, the categories of "other nonmetals" and halogens are the two most enduring nonmetal categories used in our periodic table. That was until we started complaining about what a non-informative category name "other nonmetals" was.

Now, the halogen category is consistent with the traditional aspect of teaching the periodic table by contrasting the alkali metals with the halogens.

Long story short, we don’t currently have a halogen category because we weren't able to satisfactorily characterise the other nonmetals as something other than {other nonmetals}. So we decided that they and the halogen nonmetals would collectively be the reactive nonmetals.

Developments. A couple of articles in the peer-reviewed literature have prompted me to revisit this question. The first is "Metals are not the only catalysts", in Nature. The second is "Organising the metals and nonmetals", in Foundations of Chemistry (disclaimer: 1, authored by me; 2, the scheme I propose is not the same as that in this article).

The upshot is that the other nonmetals can be characterised by their:

1. tendency to form covalent or polymeric compounds;
2. prominent biological roles;
3. proclivity to catenate i.e. form chains or rings;
4. multiple vertical, horizontal and diagonal relationships;
5. uses in, or as, combustion and explosives;
6. uses in organocatalysis; and
7. dualistic Jekyll (#2) and Hyde (#5) behaviours

The first six properties of the nonmetals in this part of the periodic table are documented in the literature. #7 is an observation by me.

Coactive. In light of properties 1, 3, 4 and 6, I suggest the term "coactive nonmetals" would be a good way of referring to the other nonmetals. The remaining nonmetals (F, Cl, Br, I) then become the halogen nonmetals, thus restoring the pre-eminence of this category. Here, we show astatine as a post-transition metal since condensed astatine is expected to be a full-fledged FCC metal.

"Coactive" means, "acting in concert; acting or taking place together". That seems like a good adjective wrt the covalent compounds of H, C, N, O, P, S and Se. For their polymeric compounds, e.g. of H, N, O or S, the connection is to the linked nature of their repeating structural units. That is how the literature tends to deal with the nonmetals, except that it has no common term for the first category. There is also the catalytic conation of "coactive".

The literature. Bear in mind the expression coactive nonmetals is not found in the literature.

That said, the complementary term "coactive metal" is found in literature, in the following senses:

• "…adding a coactive metal (such as Pt, Ir, or Rh metal)"
• "The same set of experiments was performed in presence of other co-active metal ions Fe +2, Fe +3, Co +2, Ni +2, Mn +2, Cd +2, Ca +2, Mg +2…".
• "It is of great interest and challenging to improve new catalysts that consist of any of those components and new active metal component (ie co-active metal, promoter)."

There are several other references in the literature to "co-active" elements, materials or substances, including manganese, iron, nickel, cobalt and plutonium.

In the endeavours by WP:ELEMENTS to nail the other nonmetals, we will have now gone full circle from the original {other nonmetals and halogens} → {polyatomic nonmetals and diatomic nonmetals} → {reactive nonmetals}. Now we have a putative categorisation scheme for going from {reactive nonmetals} → {coactive nonmetals} and {halogen nonmetals} that would fulfil the worthy intentions of our predecessors.

Question: Is "coactive nonmetal" a neologism or is it a descriptive phrase, c.f. "coactive metal"? If there are coactive metals does this suggest there are coactive nonmetals? The other nonmetals category is well enough seen in the literature. The covalent-polymeric, biological, catenative, interlinked, combustive/explosive, and organocatalytic properties of the nonmetals in this part of the periodic table are documented in the literature. Historically, and as noted, the "other nonmetals" category is the most enduring nonmetal category used in the Wikipedia periodic table, until we started complaining about what a non-informative category name this was. Do we now have enough content, in pursuit of a better encyclopedia, to support a change back to a binary categorisation of the nonmetals as coactive (formerly other) nonmetals, and halogen nonmetals? ♦

Thank you for alerting me about this discussion. I have replied at Wikipedia talk:WikiProject Elements#Coactive nonmetals (cont.). Dirac66 (talk) 18:32, 10 August 2020 (UTC)

Wiswesser and the Aufbau principle

Thanks for making the addition regarding Wiswesser on the Aufbau principle page. I had started to think about how to do that but found I couldn't get full access to his papers from 1945. However, I did find some extra information which you and @Double sharp: may find interesting. You two are probably much more into the history of the periodic table than I am. Wiswesser actually published three papers in consecutive issues of J. Chem. Ed.: see [2] and [3] for the second and third parts. He was obviously interested in the teaching of quantum mechanics and in this he may have been influenced by Thomas Hazlehurst, who was one of his lecturers at Lehigh University, from which he had graduated in 1936. Hazlehurst wrote a related article in 1941 [4]. Wiswesser's original has been cited a few times by significant figures in the periodic table story, notably by Ostrovsky in his 2003 chapter in the book: Fundamental World of Quantum Chemistry. (The doi I found currently fails to work). Also [5] from 2002. I can't get access to any of the full articles but I hope you might follow them up and give due credit to Wiswesser if he really was thinking ahead of his time! Michael D. Turnbull (talk) 15:49, 10 September 2020 (UTC)

Thanks for the other references. I'll have a look at those I can access. Dirac66 (talk) 17:45, 10 September 2020 (UTC)

And re Ostrovsky, I found his article on Physical Explanation of the Periodic Table at [6]. However this paper does not cite Wiswesser. Dirac66 (talk) 00:03, 11 September 2020 (UTC)

Thank you @Michael D. Turnbull: for those papers; my interest in chemistry is indeed mostly about the history of the PT. :)

Hazlehurst gives the Aufbau-order up to 7s (then he omits 5f and 6d and goes straight to 7p). However he is giving a simplified treatment with no formula, writing "It is proposed to present the actual explanation in briefest outline and then to suggest a method of presentation suitable for elementary students and plausible without being incorrect."

BTW it's very interesting to me that Hazlehurst remarks that the ordering of the subshells changes in a complicated way as Z increases. That's quite an early appearance of this correct statement, and he cites the even earlier Atoms, molecules, and quanta by Ruark and Urey (1930), pp. 245ff (though I don't have that). That's quite fascinating given how widespread the sloppy aufbau that claims 4s is always below 3d is despite how early it was known to be false. Seems like a lot of insights about the Klechkovsky rule and electron configurations that haven't percolated into textbooks may be lurking in such old back issues of the Journal of Chemical Education. Double sharp (talk) 07:48, 11 September 2020 (UTC)

@Michael D. Turnbull:@Double sharp: I have now looked at the other papers mentioned by Michael D. Turnbull. Wiswesser's Parts 2 and 3 do not return to the aufbau principle or the energy level proposed in part 1. Instead they are an introduction to concepts of atomic structure which all textbooks discuss today but which were less familiar to chemistry teachers in 1945: Lewis structures, electron waves and orbitals, quantum numbers (all 4) etc. Some mention of the periodic table but not of the aufbau principle or of Wiswesser's formula now quoted in this article. So parts 2 and 3 are not really relevant. Hazlehurst's paper does give the energy level sequence quite completely, so perhaps it should be mentioned if it adds significantly to what Madelung had previously said. I will wait for someone else to compare it with Madelung's paper since my German is too rusty. Dirac66 (talk) 00:05, 12 September 2020 (UTC)

Regarding a pdf about Ionization energy calculations

As you may know, me and my frend ponor are making extensive edits about Ionization energies, albeit I only make the facile ones. Nonetheless, I find the calculations for the IE very exiguous and lacking; a lot of residual factors are present, which however minimal, would reduce the accuracy of the computation. I concede that i do not know much of the calculations. So i came here to ask you to also help us edit. I found this pdf which can provide you information. Thank you very much! Ice bear johny (talk) 06:29, 21 September 2020 (UTC)

Hello. The problem is that the theory of the calculations is not easy. Strictly one should calculate the energies of the neutral atom and the positive ion by accurate quantum-mechanical methods and then subtract to find the ionization energy. But quantum mechanics is complicated and the equations cannot be solved exactly for two or more electrons. The paper by Lang and Smith uses an approximate formula which is reasonably accurate for one to four electrons, but it is really just a fitting formula without a quantum-mechanical basis. My opinion is that it would be best to leave the section Quantum-mechanical explanation alone, because explaining the theory for two or more electrons is too complicated for the level of this article. Also Lang and Smith mention relativistic corrections and Lamb shift. These make the theory still more complicated, and the magnitude of the corrections is quite negligible at least for light atoms, say the first half of the periodic table. Dirac66 (talk) 21:37, 22 September 2020 (UTC)

Oh wait what i didn't see your reply. Anyways, I've got a question tho, where did the computation for the quantum mechanical computation come from? I cannot validate it as there is literally no reference. Thanks and have a good day! Ice bear johny (talk) 11:14, 1 October 2020 (UTC)

It is true that the section Quantum-mechanical explanation is unsourced. I checked the article history and found that these 2 paragraphs were inserted (almost as is) in the first version of the article (after 3 versions of a redirect page) on 9 August 2005(!), by an editor Centrx who has been inactive since 2012. I will try to find some sources for this section when I can. However I have some experience in theoretical chemistry and I will tell you now that the paragraph is basically correct. There are no really satisfactory simple formulas for ionization energies of many-electron atoms, and quantum calculations are as complicated as the article now says. So really all that can be done is to provide sources for the statements which are already there. Dirac66 (talk) 15:33, 1 October 2020 (UTC)

Why decrease accuracy?

Regarding This revert

Your revert was tagged "Why make it less accurate? Reader can decide whether or not to approximate."

Because: No, they can't. They're stuck with what the author gives them, and in this case 14 digits of text is going to slow down even experienced scientists. The translation to MeV is going to be confusing enough to the non-particle-physics crowd (How can a voltage be a mass?) Not only that, but it's a weak estimation since it's already one set of units removed from the original measurement.

On that account, for READABILITY "about 1875" is vastly superior.

I maintain it should be either simplified (14 digits of accuracy is beyond absurd for a secondary measurement - 4 is more than sufficient) or eliminated altogether.

Riventree (talk) 20:21, 4 October 2020 (UTC)

I meant of course "Why make it less accurate than the source?" I believe that Wikipedia should report the source values as is, in both u and MeV, without making either of them less accurate. I think any reader who can understand what a deuteron is should be capable of rounding off either value to less digits if desired. However if s/he wants to know the value as accurately as it is known, and we give a less accurate value, then it requires extra work from the reader to look up the source of each value to find out if a more accurate value is known. Wikipedia should provide this information by retaining the accuracy of the source data. Dirac66 (talk) 20:55, 4 October 2020 (UTC)

Good thing you didn't edit the entry for Pi... that's known to 1,000,000+ digits... could be a very long first paragraph. :) Adding additional information (even when accurate) still has a cost on the reader's side. Otherwise we wouldn't have switch from "XVII" to "17". They're both exactly right, but one is much easier to read than the other. Lemme try something else...

Riventree (talk) 01:04, 5 October 2020 (UTC)

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invitations

I have posted a comment on my talk page. Perhaps you may like to comment on the topic there? I don't want to be too active on this topic, but perhaps a quiet thought or two may be useful.Chjoaygame (talk) 17:45, 12 October 2020 (UTC)

Editor PAR has started an RfC on this talk page. Perhaps it may interest you.Chjoaygame (talk) 15:11, 4 November 2020 (UTC)

A barnstar for thee

		The Editor's Barnstar
		Thank you for helping me edit Ionization energy :)))! Really appreciated your help Ice bear johny meowy123 16:41, 3 November 2020 (UTC)

		The Barnstar of Diligence
		Here's another one, for incessantly fixing my impertinent references for copyediting my wordings, fixing the veracity of my information and generally being a nice person :))) Ice bear johny meowy123 16:41, 3 November 2020 (UTC)

NaCl polyhedra

Hi, I hope you can help me out as I have nominated this image to become a Featured Picture and now there is some questions about this image.
I hope you have the knowledge to provide answers to the questions at this link. The questions are;
1) This representation is different to all the others I've Googled. Does it have Academic authentication?
2) But could you add to the description about which colors are which elements.
I'm a graphic worker and have no knowledge of this subject.
I really hope you can help me or tell me someone else who might be able, thanks. --always ping me-- Goran tek-en (talk) 17:13, 23 August 2021 (UTC)

I have got the needed information from another user so this is  Done, thanks. --always ping me-- Goran tek-en (talk) 19:54, 23 August 2021 (UTC)

Nitrogen ice

See my talk comment on the phase diagram page. I watched as floating chunks of solid N2 formed as I pumped on the liquid - eventually freezing the whole dewar solid from top to bottom at 54K. Experimental evidence. Bscip (talk) 19:40, 25 August 2021 (UTC)

Principal series (spectroscopy) moved to draftspace

An article you recently created, Principal series (spectroscopy), is not suitable as written to remain published. It needs citations from reliable, independent sources. (?) Information that can't be referenced should be removed (verifiability is of central importance on Wikipedia). I've moved your draft to draftspace (with a prefix of "Draft:" before the article title) where you can incubate the article with minimal disruption. When you feel the article meets Wikipedia's general notability guideline and thus is ready for mainspace, please click on the "Submit your draft for review!" button at the top of the page. John B123 (talk) 20:56, 4 September 2021 (UTC)

@John B123: :@Graeme Bartlett: OK. Graeme Bartlett has added content, and I have added 3 sources plus a little content. However I cannot find the "Submit your draft for review!" button (perhaps I have a different computer system), so could you please review the article and restore it to mainspace. Dirac66 (talk) 22:07, 5 September 2021 (UTC)

I took that button off as I would just move it back without using other AFC review time. Graeme Bartlett (talk) 22:09, 5 September 2021 (UTC)

OK, thank you both. Dirac66 (talk) 23:29, 5 September 2021 (UTC)

Nonmetal at FAC

G'day Dirac66. Are you able to chime in to the FAC nomination for this one? Thank you, Sandbh (talk) 07:05, 5 November 2021 (UTC)

Bonjour Sandbh. I have now added a suggestion to this discussion. Dirac66 (talk) 21:11, 6 November 2021 (UTC)

Regarding a nonmetal criterion

I've suggested in some conversations with Sandbh, Droog Andrey and others (both on- and off-WP) that a good refinement to the Britannica definition (which is more or less a solid-state physics one) for chemistry would be to say: a nonmetal is an element that has a finite band gap for electron conduction in at least one stable or metastable allotrope at standard conditions. The point being that this lets us define metallicity for elements, which can have multiple allotropes, rather than just substances. It clearly rules out carbon (diamond) which really shouldn't be a metal speaking chemically. Gray tin is a semimetal by band structure, so tin remains a metal under this scheme.

The result is also consistent with another way to look at it. Well, looking at most stable allotropes, Ge and Se are semiconductors, but As is a semimetal again. But we can interpolate and see that band gaps open in GeAs and AsSe systems, so it makes sense that the metal-nonmetal line should be drawn before Ge. This is Droog Andrey's neighbour criterion: you adjudicate metallicity for element X by checking the element itself and compounds with the two neighbours in the sense of atomic number. If metallic bonding is the majority, X is a metal; if covalent/ionic bonding is the majority, it's an nonmetal; if non-bonding is the majority, it's a noble gas. A three-way tie never happens within known elements, since astatine turns out to be a metal after all when calculated fully. (Not sure how hydrogen is dealt with in his scheme, but I suppose one can use lithium to break the tie.) And possibly with the exception of antimony it gives the same results as the allotrope-based criterion.

Of course it's OR and we can't use it, but given your comment at the nonmetal FAC, I thought it might interest you. It does pretty much reproduce a common line in Russian texts. :) Double sharp (talk) 00:16, 18 November 2021 (UTC)

This does sound like an interesting criterion to include, if we can find a source. It is permissible to cite sources in other languages (see WP:TRANSCRIPTION), so we could cite a suitable Russian text accompanied by a translation of the essential passages. Dirac66 (talk) 01:10, 18 November 2021 (UTC)

Oh, what I meant is that I can find Russian texts giving the same line that this criterion gives. The problem is that I don't see them formalising how they got to it. See for example this 8th-9th grade textbook by S. T. Zhukov. He writes Металл – простое вещество, в котором атомы связаны между собой металлической связью. (Metal – a simple substance whose atoms are bonded together by a metallic bond.) And later he writes Именно в этих группах наиболее четко прослеживается граница между элементами, образующими металлы (орбитальный радиус больше 1,1 ангстрема), и элементами, образующими неметаллы (орбитальный радиус меньше 1,1 ангстрема). "It is in these groups [13, 14, and 15] that the boundary between the elements forming metals (the orbital radius is greater than 1.1 angstroms) and the elements forming non-metals (the orbital radius is less than 1.1 angstroms) is most clearly traced." So he speaks about the boundary between elements forming metals and elements forming nonmetals, making a distinction between the element and the simple substance as he does throughout his text. Unfortunately, he doesn't state how he considers the allotrope problem, but C and As are put on the nonmetals' side. My suspicions are raised by the fact that he talks about yellow arsenic, but in the absence of a precise statement, I have to keep looking. :( Double sharp (talk) 10:06, 18 November 2021 (UTC)

Looking at orbital radii[7], 1.2 Å seems to be the turning point. All nonmetals have orbital radii < 1.2 Å. While this ropes in Hg, Pd, Zn, Be, Cd, Co, Cu, Au, Ni and Zn too these all have valence bands substantially overlapping their conduction bands whereas this is not the case for the nonmetals. Sandbh (talk) 22:38, 18 November 2021 (UTC)

I think the anomalously low value for Pd comes from ignoring the 5s and 5p orbitals as empty in a gas-phase Pd⁰ atom. Anyway it's only a rough guide: radon has larger orbital radius than zinc. Double sharp (talk) 10:48, 19 November 2021 (UTC)

Also, I think Zhukov is using "metal" to mean "a simple substance characterised by metallic bonding". So orbital radius is not his definition, and he's just making the point that large atoms "find it easier" to go for metallic bonding. He focuses mostly on the main-group, where as a rough guide 1.1 Å is more or less correct anyway, except for beryllium. (Maybe grey arsenic if you want to get picky about allotropes, except that delocalisation is clearly stronger in some directions of grey arsenic crystal than others, so it's a borderline case anyway.) Double sharp (talk) 14:33, 20 November 2021 (UTC)

a tedious matter

Hi, Dirac66. I am sorry that I feel a need to ask your advice on a tedious matter. I have posted about it here.Chjoaygame (talk) 15:45, 17 December 2021 (UTC)

I see that the editor in question has not replied to you after 2 days. We do not really have evidence of his/her identity and of a conflict of interest. It is true that he/she has written most of the article, being the author of 95.6% of the text according to the Page statistics as of today. However, this could just indicate that he/she is the only Wiki editor who is interested in the subject of Prokovskii. There are other articles which only have one major author.

In the absence of further evidence that the authorship of the article may be tainted by conflict of interest, it might be more productive to criticize the visible weak points of the article. One visible problem is the predominance of primary references: the list of references has 18 items of which 16 have Prokovskii himself as author or co-author. The only exceptions are 1. Who’s who in the world 2016 which I could not consult due to a dead link, and 10. Best Reference Books – Polymer Dynamics which admittedly does have Prokovskii’s book on the list. I think the article needs further secondary sources not written or co-written by Prokovskii in order to establish that he is really notable. If you want to get further involved with this article, perhaps this is a point you could make. Dirac66 (talk) 17:09, 19 December 2021 (UTC)

Thank you for your wise thoughts. This thing spreads over many articles. I don't want to get involved.Chjoaygame (talk) 10:15, 20 December 2021 (UTC)

I understand. However in case you do decide to intervene in this or a similar case, I saw today a possible model to follow for an intervention. See https://en.wikipedia.org/w/index.php?title=Hydrogen_peroxide&curid=14403&diff=1061588001&oldid=1061583964 and also DMacks' intervention today at User talk:Bjarni-thorgeirsson. Dirac66 (talk) 19:40, 22 December 2021 (UTC)

Thank you.Chjoaygame (talk) 12:03, 30 December 2021 (UTC)