Question

Au is the only metal which can form CsAu ..explain​

Answer 1

Answer:

Hi everyone,

Why do caesium and gold form an ionic compound, rather than an alloy?

The only idea I have for explaining this is that being at the bottom of Group 1, electrons are much more easily taken from Cs' outer valence orbital (than say, K) and therefore there is a greater energetic likelihood that they will be localised in an ionic bond... perhaps you could say the enthalpy of lattice formation is greater (than for, KAu for example)... I'm not sure that argument really dispels the idea that CsAu could be an alloy.

I think at the root of my apprehension is that I don't really know what favours ionic over metallic bonding (and vice versa).