Do ionic or metallic structures have higher melting points?

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Randomusername5
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Do Ionic or metallic structures have higher melting points?
Do ions not undergo disproportionation? Why? e.g. HBr(aq) + Cl-(aq)
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seals2001
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(Original post by Randomusername5)
Do Ionic or metallic structures have higher melting points?
Do ions not undergo disproportionation? Why? e.g. HBr(aq) + Cl-(aq)
Ionic generally have larger melting points, because the ions are fixed in place whereas electrons are free moving in metals so more easily lost. This is a trade off though because it makes ionic compounds really brittle.

But it's hard to make that comparison because you need to consider factors like charge and ionic radius. I.e the charge density.

Its harder to compare the groups holistically and is more accurate and reliable to compare on an individual scale.
Last edited by seals2001; 4 weeks ago
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Pigster
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(Original post by Randomusername5)
Do Ionic or metallic structures have higher melting points?
Do ions not undergo disproportionation? Why? e.g. HBr(aq) + Cl-(aq)
Tungsten metal = 3687 K
Mercury = 234 K
MgO = 3125 K (I am sure there will be higher, but I can't be bothered to find them)
HgI = 532 K (there are ionic liquids at RTP, you can look them up, if you like)
My point: there is a range of values for both. The question, "which one is higher" makes no sense.

Lots of disproportionation reactions involve ions: 2Sn^2+ → Sn^4+ + Sn, 2S2O4^2− + H2O → S2O3^2− + 2HSO3^− etc.
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