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Topic: Band Theory  (Read 2648 times)

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Offline zephyrblows

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Band Theory
« on: December 17, 2006, 08:57:20 AM »
Yuck! It's so tiring to try to understand band theory qualitatively :'(

Why don't metallic solids have energy gaps? The larger the degree to which atomic orbitals overlap, the greater the energy difference between bonding and nonbonding molecular orbitals. However, the overlap degree of metals seems to be larger than that of nonmetals (the orbitals of metallic atoms are diffuse)...Is that only because electrons share more orbitals in metals?

What does this sentence mean?
"A semi-metal is defined as a material where the full and empty bands of molecular orbitals coincide in energy but with 0 energy levels per unit energy increment. "

In what case do bands "overlap?" Aren't these bands produced by overlap of atomic orbitals? Why, then, do they overlap again?

Thank you very very much!!!!!

Offline Dan

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Re: Band Theory
« Reply #1 on: December 17, 2006, 09:33:57 AM »
I found band theory confusing too. I'd recommend getting hold of "The electronic structure and chemistry of solids" by Cox - really really good book for solid state.

If you can't find it in a science library, request that the get it in, because this book kicks serious  posterior. Incredibly well written, concepts very well explained. It costs a small fortune though (considering it's a small paperback).

This isn't one of my best areas of chemistry, so I'm going to leave it at that because I don't want to confuse you further.
« Last Edit: December 17, 2006, 09:39:25 AM by Dan »
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