Question

A cubic solid is made up of two elements X and Y. Atoms ‘Y’ are present at the comers of the cube and atoms X at the body center. What is the formula of the compound? What are the coordination numbers of X and Y?

Answer 1

As Y atoms are present at 8 comers, of the cube, the number of atoms of Y in the unit cell

= 1/8 × 8

= 1

As atoms X are present at the body center, therefore, the number of atoms of X in the unit cell = 1.

∴ Ratio of atoms X : Y = 1 : 1

Hence the formula of the compound is XY.

The coordination number of each X and Y = 8.