Talk:Nonmetal

Timeline accuracy

I don't know who cobbled this together, but the dates don't check out on many things. For instance, the so-called Mott criteria, supposedly suggested in 2020. Work on this goes back to Goldhammer (1913) and Herzfeld (1927). Mott wrote about it in his book in 1990, but he came up with that criteria way back (1961? doi:10.1080/14786436108243318).

And yet we say 2020 because come people wrote a paper using the Mott criterion in 2020.

Utter. Nonsense.

This whole section should be jettisoned until we have actual sources discussing the actual history of metals.

Headbomb {t · c · p · b} 02:11, 6 August 2024 (UTC)

Yup, the dates are horrible and many of the sources don't verify (see my ever growing list #Dubious cites). Plus the most important definition, band structure, is conspicuously absent despite appearing in numerous chemistry texts books. It needs to be there. Ldm1954 (talk) 02:26, 6 August 2024 (UTC)

Yes, the Mott criterion was not first proposed in 2020. The original formulation dates back to Nevill Mott’s 1961 paper ("The transition to the metallic state", Philosophical Magazine, 6:287–309) and has a rich theoretical lineage, including precursor ideas from Goldhammer (1913) and Herzfeld (1927).

The 2020 paper cited in the table does not claim to have originated the Mott criterion. Rather, it applies the existing criterion to the periodic table under ambient conditions, proposing that the dividing line between metals and nonmetals lies at a Mott parameter value of ~0.45, instead of the original ~0.25 value derived for T = 0 K. This represents a recalibration, not a reinvention. The relevance of ambient contitions is set out in the hatnote in the Definition and applicable elements section: "Unless otherwise noted, this article describes the stable form of an element at standard temperature and pressure (STP)"

That said, the article should clarify this distinction to avoid any implication that the criterion was developed in 2020. I've augmented the footnote to this end.

Thanks for catching this — it's an important nuance to get right. Sandbh (talk) 05:50, 4 April 2025 (UTC)

Band structure has been there since Aug 3, 2024, thanks to User: Headbomb. --- Sandbh (talk) 05:59, 4 April 2025 (UTC)

I just shitcanned the whole section as hopeless. Headbomb {t · c · p · b} 20:23, 4 April 2025 (UTC)

I'm glad I took a 7-month editing break from this article.

Leaving behind the contentious timeline table, I have added a trimmed, copyedited and reorganised "Suggested distinguishing criteria" section.

The flow is from conceptual non-agreement, to a single criterion, then to empirical examples: one property; two properties; multiple properties. Sandbh (talk) 04:44, 5 April 2025 (UTC)

Checking citations

@Ldm1954, Johnjbarton, and YBG: I plan to start progressively checking the citations in the article, from #1 onwards, to ensure they support the statements they're attached to. I'll post my findings here, probably in batches of 10 at a time, for transparency and discussion. Looking forward to any input others might have along the way. Sandbh (talk) 04:18, 4 April 2025 (UTC)

Dubious tag: As and Sb

The article currently says:

One widely recognized physical property is the temperature coefficient of resistivity—that is, the way an element’s conductivity changes with temperature. In metals, conductivity typically decreases with increasing temperature, whereas in nonmetals it increases. However, there are notable exceptions. For instance, plutonium, although a metal, exhibits increased conductivity when heated from −175 °C to +125 °C. Conversely, carbon (as its graphite allotrope), often described as nonmetallic, behaves as a semimetal and shows decreased conductivity with temperature. [Atkins et al. 2006, pp. 320–21] Arsenic and antimony, sometimes classified as nonmetals, behave in the same way. [Zhigal'skii & Jones 2003, p. 66]^{[dubious – discuss]}

The reason given for the tag is: "No such statements appear in the more recent 9th and other editions, so unverifiable."

AFAIK, since As and Sb are semimetals in the physics-based sense and do behave in the same manner as graphite, and since there is no 9th edition of either Atkins et al. or Zhigal'skii & Jones, I have removed the dubious tag. Sandbh (talk) 05:11, 5 April 2025 (UTC)

Sandbh, please stop

@Sandbh, sorry but you are again making unilateral changes based upon your own opinion which is not shared. Rather than attempting to seek consensus, for instance by making suggestions in a Sandbox, you are just deleting/editing. This is not how concensus is generated on Wikipedia, so please only make changes for which there is consensus. I am reverting your recent edits. Ldm1954 (talk) 15:45, 5 April 2025 (UTC)

Historical non-metal confusion is no longer relevant.

Science moves forward. Before modern quantum computational chemistry methods the distinction between different materials was less clear; this was even more so back when computers were less powerful than a modern smart phone. The confusion about metal/non-metal etc is now a historical anomaly. This article must reflect 21st century knowledge, not history as otherwise it is misleading. The definitions of metal, semimental etc are no longer an issue. Sections that confuse them here can get moved into an article of history, but not the material we provide the general public as encyclopedic knowledge. Ldm1954 (talk) 15:53, 5 April 2025 (UTC)