Which ionic compound has the smallest electronegativity difference?

Question

Considering binary ionic compounds, which ionic compound contains two elements that are closest to each other in terms of electronegativity?

Answer 1

This almost seems like a "trick" question, but a cursory review of the periodic table shows a few combination of metals and non metals that have the same electronegativity value.  If you take "ionic compound" as meaning the combination of a metal and non metal, then a couple of examples where ∆EN is zeo would be cobalt silicide and molybdenum phosphide.  Others with ∆EN = 0.1 might be gold sulfide (not really an ionic compound however).  You can look to see other metal/non metals combinations with ∆EN values of 0.2 or 0.3 etc.  If one had to give only a single answer, it might well be cobalt silicide.