A solid has a cubic structure in which X atoms are located at the corners of the cube, Y atoms are at the cube centres, and O atoms are at the edge centers. What is the formula of the compound is XYOa?. The value of a is

Atoms of X are present at all eight corners of the cube. Therefore, each atom of X at the corner makes 1/8 contribution toward the unit cell. Number of atoms of X per unit cell =8×18=1Y atom is present at the body center, thus contribution of Y toward unit cell- 1× 1= IO atom is present at each of the edge center (number of edges of cube = 12)And each O atom present at edge center will make 1/4 contribution toward the unit cell. The number of O atoms per unit cell =12×14=3The formula of the compound is, therefore, XYO3