In a crystalline solid, having formula XY ₂ O ₄ , oxide ions are arranged in cubic close packed lattice while, cations X are present is tetrahedral voids and cations Y are present in octahedral voids. The percentage of tetrahedral voids occupied by X is

Step-by-step solution

In a cubic close packed lattice of oxide ions, there would be two tetrahedral and one octahedral void per oxide ion. Since, the formula shows the presence of 4 oxide ions, the number of tetrahedral voids is eight and that of octahedral voids is four. Out of the eight tetrahedral voids, one is occupied by X . Percentage of tetrahedral voids occupied = 1 8 100=12.5 %