Why two non-metals can combine to form a compound but two metals cannot?

Answer 1

Two metals can not form a compound like two non metals can because

of alloys, or is it cations or anions.

I think this is the answer i took chemistry 3 years ago sorry if this is not right.

Answer 2

It has to do with a property called electronegativity, which is how much a certain element will pull on an electron. Nonmetals have fairly high electronegative values. Because these values are high enough and close enough no nonmetal has the ability to completely pull electrons away from another. Metals, by contrast, have low electronegativity values and so do not expert a strong pull on electrons. Because of this many of the nonmetals can pull away electrons from the valence shell of a metal.

Answer 3

First an explanation in terms of ionization energy and electron affinity:

Metals have low ionization energies and readily form ions. Non-metals have high electron affinities- so put them together and electron transfer is favourable.

Two bonded non metals are generally covalent- their ionization energies are high.

Now an explanation in terms of electronegativity (electronegativity is related to ionization energy and elctron affinity)

metals have low electronegativity- non metals are comparativelly high. So electron transfer is likely.

Just a cautionary word about compounds of non metals never being ionic-- what about PBr5- a binary compound of two non metals- in the solid state this has the structure PBr4+ Br-...bit of a cheat really as there is a polyatomic ion in there but it is ionic!