Talk:Metal

The color coding of the chart under "Periodic table distribution of elemental metals" is absolutely hostile from an accessibility point of view. Having three shades of blue/violet is just plain ridiculous and almost requires going out of your way to making it difficult to impossible for colorblind individuals to see. Please change the charting to high contrast colors. — Preceding unsigned comment added by 2600:4040:B07B:9700:344D:4544:B11D:30AC (talk) 23:55, 20 May 2025 (UTC)

Please read Wikipedia:Civility and edit you comment accordingly. Johnjbarton (talk) 00:09, 21 May 2025 (UTC)

Article says "In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero.[2]" - Is it "generally regarded" or just one persons idea ? It's a very theoretical definition rather than being something that can be tested or measured. If true, it would make all materials, while superconducting, metals. A more usual definition of a metal might be having free electrons in a conduction band ? - Rod57 (talk) 12:33, 12 March 2024 (UTC)

The source is Nevill Mott. If you have another source, please let's have it. Johnjbarton (talk) 15:28, 2 May 2024 (UTC)

The electrical and thermal section read, in part:

"Plutonium increases its electrical conductivity when heated in the temperature range of around −175 to +125 °C, with anomalously large thermal expansion coefficient and a phase change from monoclinic to face-centered cubic near 100 °C."

The source was given as Hecker, Siegfried S. (2000). "Plutonium and its alloys: from atoms to microstructure" (PDF). Los Alamos Science. 26: 290–335.

Reading the source, it does not say anything about:

• Pu increasing its electrical conductivity when heated in the temperature range of around −175 to +125 °C; nor
• an "anomalously large" thermal expansion coefficient.

Nor did the article's citation give a page number/s specifying where the pertient facts were mentioned.

OTOH, Russell AM & Lee KL 2005, Structure-Property Relations in Nonferrous Metals, Wiley-Interscience, New York, p. 466, say that when Pu (a metal) is heated within a temperature range of 100 to 400K [–173 to 126.85 °C] its conductivity increases.

The same source shows that the simple monoclinic phase of Pu is stable below 122 °C (p. 465).

I have therefore amended the mention of Pu to read...

"Plutonium increases its electrical conductivity when heated in the temperature range of around −175 to +125 °C"

...and added a citation to Russel & Lee, with a page number.

Since the fact that Pu undergoes a phase change from simple monoclinic to body-centred monoclinic is not germane to the point about its unusual tempertaure coefficient of resistivity, I've removed it. --- Sandbh (talk) 13:03, 20 June 2024 (UTC)

Please do more reading on fundamental physics, and careful analysis, see for instance https://www.rmcybernetics.com/science/diy-experiments/heat-and-resistivity#:~:text=The%20temperature%20affects%20the%20dimensions,flow%20than%20a%20thinner%20one or many other introductions to physics. With anomalous expansion, as in Pu this will have a large effect. Ldm1954 (talk) 11:24, 22 June 2024 (UTC)

The lede says:

A metal (from Ancient Greek μέταλλον (métallon) 'mine, quarry, metal') is a material that when polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. These properties are all associated with having electrons available at the Fermi level, as against nonmetallic materials which do not.^[1][2]

Neither cite [1] not cite [2] say that nonmetallic materials do not have electrons available at the Fermi level.

[1] Kittel, Charles (2018). Introduction to solid state physics. Paul McEuen (Global edition, [9th edition] ed.). Hoboken, NJ: Wiley. ISBN 978-1-119-45416-8. [2] Ashcroft, Neil W.; Mermin, N. David (1976). Solid state physics. New York: Holt, Rinehart and Winston. ISBN 978-0-03-083993-1.
— Sandbh (talk) 04:28, 28 June 2024 (UTC)

@Ldm1954: In this edit the reasons you gave for removing the disupted tags were:

"Added specific chapters. Those exact words are not used, but the science explained in those chapters is equivalent. It matters to read and understand."

Your reasoning breaches WP:NOR i.e. no orginal research. Neither source explicitly makes the statements concerned. --- Sandbh (talk) 13:20, 29 June 2024 (UTC)

Neither source has to make exactly that statement. What is included is a rephrasing which is covered in all solid state physics books. Unfortunately you believe that sources must be verbatim, this is wrong. If you want to challenge this I will post on WP:PHYSICS, I know what the response will be. Ldm1954 (talk) 13:49, 29 June 2024 (UTC)

Please comment here, or just edit. Ldm1954 (talk) 13:44, 19 July 2024 (UTC)

@Marchantiophyta, there is a looooong history to why the Fermi energy is mentioned in the first paragraph. The change you made implies that the characteristics of a metal are that it is "when polished or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well....and ductile". This is a phenomenological definition which, rigorously, is misleading. The addition of E_f up front is because that is the true definition of a metal, the properties are consequences.

We can discuss wordsmithing here more, but the key fact of what makes a metal a metal has been a near endless fight (as has nonmetal). Ldm1954 (talk) 01:03, 6 August 2025 (UTC)

Hello! I get where you're coming from and am happy to try and hash out some mutually agreeable solution here. I see two issues with the wording as it stands:

1) - WP:EXPLAINLEAD and WP:UPFRONT are crystal clear here – the introduction, and particularly the crucial first paragraph, need to be comprehensible to a general audience. This is all the more important for a general-interest article like this one; complicated concepts are unavoidable here, but the Venn diagram of “people who’ve heard of the Fermi level” and “people who want to learn what a metal is” is effectively two distinct circles.

2) - Your assertion that E_F is the “true definition of a metal” is incorrect. The astronomer’s definition of metal (anything other than H or He) is equally valid and equally baffling to a layreader unfamiliar with Fermi levels or Fraunhofer lines alike. An astronomer could very well swap their definition in place of yours in good faith or, in a scientific Judgement of Solomon, propose that neither definition be included given the lack of common ground between them.

I also disagree with the notion that opening with a phenomenological definition is somehow improper – consider the article on nonmetals, whose first paragraph solely describes what they’re usually like and how they generally behave; or consider the article on metalloids, which opens by admitting that no definitive definition exists for the subject in question (admittedly WP:OTHERCONTENT, but you get what I’m saying). Properties and observable characteristics are well-suited to the opening sections of articles because they’re easily understood and “set the stage” for more involved discussions on their causes.

All that being said, I agree that it's important to include E_F in the lead - it's really just a matter where it's most appropriate.

Best,

Marchantiophyta (talk) 02:51, 6 August 2025 (UTC)

Please see the prior talk page above, the talk page (+archives) of Talk:Nonmetal, Nonmetallic material + talk, Talk:Heavy metals (and there are a few others). Courtesy ping of @Johnjbarton. Ldm1954 (talk) 03:18, 6 August 2025 (UTC)

The astronomer's definition of metal is a distinct concept that should not be confused with this discussion. It has its own page at Metallicity. This page is about the primary meaning of the word "metal".

I do find the proposed version of the lede better than the current one: it has better structure and is more accessible. There the first sentence should not be understood as a definition but as merely a relatively vague description. However, the sentence The valence electrons of metals are found at or around the Fermi level should be reformulated (remove "or around"?). The strict definition of a metal is that there is no excitation gap, and "around" would only be appropriate for a small-gap semiconductor. Jähmefyysikko (talk) 03:56, 6 August 2025 (UTC)

I agree about "at or around" being not right. I also don't like the word "characteristically". Also the statement about "sharing" is a bit too high-school for me.

I still think the proposed 1st paragraph implies that these properties are what defines a metal, which I 100% want to avoid. If we revise to indicate that these are not defining characteristics then I am OK with it. (Remember that some very elementary texts have defined metals via those properties.) Ldm1954 (talk) 04:24, 6 August 2025 (UTC)

Perhaps modify the third paragraph to explicitly say something along the lines of The defining property of a metal is [something about low-energy excitations/Fermi level]? This would imply that the previous descriptions were not defining. A good reference would make such a statement stronger. I agree about "characteristically" and "sharing". Jähmefyysikko (talk) 05:54, 6 August 2025 (UTC)

For the 1st paragraph, how about:

A metal (from Ancient Greek μέταλλον (métallon) 'mine, quarry, metal') is a material that has metallic bonding. When polished or fractured, they typically shows a lustrous appearance, and conduct electricity and heat relatively well. Metals are frequently ductile (can be drawn into a wire) and malleable (can be shaped via hammering or pressing).[1]

Ldm1954 (talk) 09:00, 6 August 2025 (UTC)

I agree the Fermi level defn is essential. Maybe we just need to work in a description of the Fermi worked into the sentence or even adding another sentence to clarify. Johnjbarton (talk) 02:28, 7 August 2025 (UTC)