Question

hi all,
can any body tell me what make Aluminum oxide an insulator?

Answer 1

I would guess that forming bonds with oxygen reduces the amount of electrons available for conduction.

Recall that in metals, the outer electrons are loosely bond and thus will be able "move" when an potential difference is applied.

In aluminium oxide, the loose electrons from the aluminium atom is lost to the oxygen, which will "cherish" the electrons because now the oxygen attains octet configuration.

Another way to look at it is that in aluminium oxide, the conduction band is higher than that of aluminium metal. I try not to elaborate on this because it might get difficult if you are not comfortable with working with energy levels.

Answer 2

plz elobrate you answer with energy level i can understand energy levels