Question

In the crystal structure of potassium oxide, the oxide ions are coordinated by eight potassium ions. part a what is the coordination number of potassium? g

Answer 1

Potassium oxide has the antifluorite structure. The antifluorite structure have compounds with the stoichiometry X₂Y, where X is the cation and Y is the anion. In the antifluorite structure positions of the cations and anions are reversed relative to their positions in calcium fluoride.
Potassium ions coordinated to 4 oxide ions, potassium ions are all in the tetrahedral holes.