Talk:Hume-Rothery rules

Valency rules
this page is wrong! its metals with a higher valency are more likely to dissolve in lower valency. check Smallman and Bishop, metals and materials.


 * The above error has been corrected. Eldin raigmore (talk) 23:21, 22 January 2018 (UTC)
 * Several sources say that the lower-valency metal is likelier to dissolve in the higher-valency metal. The sources contradict each other.  With only one source cited there's a 50% chance this statement is wrong. and and for examples. Eldin raigmore (talk) 22:59, 24 January 2018 (UTC)

Other rules?
Presently only solubility rules are listed... Shouldn't there be rules referring to an average electron count and how special values of electron counts relate to whether and (what type of) compounds are formed? If anyone has them handy please add!! 128.97.82.220 (talk) 00:39, 5 November 2010 (UTC)


 * I disagree. This article is about solubility rules; so there needn't be anything about compounds other than the rules that make them less likely than a solid solution.  Furthermore, although more modern research does take notice of how the electron density etc. affect solubility, that isn't the Hume-Rothery rules; in the 1930s and 1950s Hume-Rothery didn't publish anything about that.  Perhaps a "further reading" note, that mentions this more modern research, and/or points to a Wikipedia article about it, would be a good thing.  But that's the limit.  (In my opinion! I suppose I could be wrong.) Eldin raigmore (talk) 23:04, 24 January 2018 (UTC)


 * Perhaps there should be an article about Hume-Rothery phases or Hume-Rothery compounds or Hume-Rothery electron whatever. There may already be such an article. If not you should add one; or add a section to the appropriate article. But it would be about inter metallic compounds, not about solid solutions; so, welcome though it would be, it wouldn’t belong here. Eldin raigmore (talk) 18:26, 26 January 2018 (UTC)

"Wide range of composition" rule 3 for interstitials
What does rule 3 for interstitials, "They should show a wide range of composition", mean? It can't mean "they should be intersoluble in each other at a wide range of concentrations", because that would be circular; it would be answering the question "how can we tell if they're intersoluble?" by answering "(Among other things), if they're pretty intersoluble, they should be intersoluble.". It can't mean "They should form a wide variety of compounds of different stoichiometries", because that would defeat the purpose of the rules about electronegativity and valence, which are meant to keep them from forming compounds at all. So what the heck does it mean? Eldin raigmore (talk) 22:57, 22 January 2018 (UTC)

I added a "confusing" template after the confusing statement. I also added a "citation needed" template after it. If a source had been indicated, perhaps I could have looked up the original, and figured out myself what it meant, and been "bold" enough to clarify it myself. But no reference was cited. Eldin raigmore (talk) 23:17, 22 January 2018 (UTC)

/* Interstitial solid solution rules */  The questionable language about “a wide range of composition” is missing from every reputable Independent secondary source. So I removed it. Eldin raigmore (talk) 17:41, 21 September 2020 (UTC)

Atomic size rule for interstitial solutions.
For an interstitial solid solution to form, the solute's atoms' radii must not be larger than 59% of the solvent's atoms' radii. This limit is larger than the size that will fit into the octahedral interstices of a close-packed solvent; that limit is about 41.4214% of the solvent's atoms' radii. Eldin raigmore (talk) 23:27, 24 January 2018 (UTC)

/* Interstitial solid solution rules */ Solute atoms’ radius should be <= 59% of solvent atoms’ radius. Eldin raigmore (talk) 17:46, 21 September 2020 (UTC)

However carbon atoms’ diameter is 170 picometers and iron atoms’ diameter is 250 picometers. So that is a size-ratio of 68%, a good bit bigger than 59%. And even moreso than 41%. Steel is carbon dissolved in iron. Clearly an interstitial solution can form with solute atoms bigger than 59% of solvent atoms. It can’t form at very high concentrations; the limit on how much carbon can dissolve in iron is lower because the carbon distorts the body-centered cubic crystal lattice of the iron too much, because the carbon atoms are too large to fit neatly entirely within the voids without pushing some of the iron atoms a little out of place. Eldin raigmore (talk) 11:21, 5 October 2020 (UTC)

Help me! This article has several issues I don’t know how to resolve!
Eldin raigmore (talk) 18:35, 26 January 2018 (UTC) Eldin raigmore (talk) 18:35, 26 January 2018 (UTC)


 * Hi . I recieved your help request - Unfortunately, you don't seem to have asked a question: I noticed some of your edit summaries but I'd like clarification on what you need help with! If you can explain what the issue is, me or one of the other helpers will be glad to help out. -- Cheers, Alfie. (Say Hi!) 20:04, 26 January 2018 (UTC)


 * The two problems which first come to mind are the following: (1) In the Substitutional part; about the solubility when the solute and solvent have different valences; I can’t find out whether a lower-Valency solute dissolves better in a higher-valence solvent, or instead a higher-valence solute dissolves better in a lower-valence solvent. Most of the Google hits on the question seem to be mere slavish copies of this article. Is there some way to find out what the true original source said? If so, I don’t it’s available to me. And would a single primary source be enough to justify putting in the correct answer (whatever it is)?  Or would it be best just to delete that one clause on the grounds that 2ndary and/or tertiary sources contradict each other?  (2) In the Interstitial section: the rule about “they must show a wide range of composition” doesn’t make any sense. Most (all?) of the Google hits that include this rule seem to be ripping off Wikipedia (this article). Most (all?) that don’t seem like plagiarism, seem not to have a similar rule at all; nor any replacement rule. Should I just delete that rule?  ——  Thanks! Eldin raigmore (talk) 20:25, 26 January 2018 (UTC)


 * This is a difficult one! I would suggest you be WP:BOLD and remove the information you can't locate reliable sources for (see WP:RS before you do this, mind). Regarding the original source, I'm afraid you'll probably have to try a university library or similar. I'm sorry I couldn't be of more help here - It's maybe also worth asking at WikiProject_Science, because someone there may be knowledgable on the topic or have access to some wonderfully useful book sources. Let me know if there's anything else I can do! -- Cheers, Alfie. (Say Hi!) 21:22, 26 January 2018 (UTC)