A compound X and Y crystallises in the cubic structure in which Y atoms are at the corners and X atoms are at the alternate faces of the cube. Find the formulate of the compound.

Explanation

In a cube, A atom are at the 8 comer, each shared by 8 cube.
The no. of Y atoms in the unit cell is 8/8 = 1
B atoms are at the comer of 6 faces and each face shared by two cubes, Therefore,
The no. of X atoms 2/2 = 1 (Alternating faces)
The formula is XY.