Question

A mineral having the formula `AB_(2)` crytallises in the cubic close-packed lattice, with the A atoms occupying the lattice points. What is the coordination number of the A atoms and B atoms ? What percentage fraction of the tetrahedral sites is occupied by B atoms ?

Answer 1

C.N. of A atom = 8, C.N. of B atom = 4
tetrahedral sites occupied by atoms B = 100% (all tetrahedral voids are occupied)