Question

A binary solid x+ y- has a zinc blende structure with y- ions forming the lattice and x+ ion occupying 25% tetrahedral sites. the formula of the solid is

Answer 1

Let no. of unit cells = n.Then , no of Tetrahedral voids = 2n .
25% ot this = 2n/4 = n/2.
So the required formula is Xn/2Yn or XY2 .