# Why are the oxide materials insulating?

Why are the oxides usually insulating? It would be nice to get an explanation with chemistry terms (e.g., electronegativity, electron affinity, etc...) and a different explanation involving the language of band structure (i.e. energy gaps).

• Without defining the temperature which you have in mind, the question is meaningless. Oxides are not metals, in the first place, and as non-metals most of them have a rather big gap in electron band. So, most of them are isolators at room temperature and semiconductors at appropriate themperatures or when doped with some foreign elements. – Georg Apr 16 '13 at 11:19
• He didn't even say whether he meant thermally or electrically insulating- which one? – user2617804 Nov 10 '13 at 12:07
• I meant electrically insulating and at room temperature. Perhaps my question would be best worded as, "Why do oxides tend to have large band gaps?" – ChickenGod Nov 12 '13 at 2:22
• I don't see how would one able correctly describe band properties without band structure, based on some chemical concept rather limited. Maybe some simple, and somewhat wrong explanation like "they have ionic bonds due to large electronegativity difference between metal and oxygen". Note that there are small bandgap oxides, semi-metals, even metals. Some, like $ReO_3$ are highly conducting that cannot be explained by electronegativity. – Greg Sep 10 '14 at 2:44