A compound formed by elements A and B has a cubic structure in which A atoms are at the corner of the cube and B atoms are at the face centres. Derive the fomula of the compound.

Explanation

As A atoms are present at the 8 corners of the cube, therefore, number of atoms of A in the unit cell ` 1/8xx 8=1`
As b atoms are present at the face centres of the 6 faces of the cube, therefore, number of atoms of B in the unit cell =` 1/2 xx 6=3`
Ratio of atoms A:B =1 :3`