Question

Calculate the number of atoms in a cubic based unit cell having one atom on each corner and two atoms on each body diagonal.

Answer 1

There are four body diagonals and atoms on the body diagonal are not shared by any other unit cell.

$\therefore$ Atoms at the corner=$8\times \frac{1}{8}$ = 1

Atoms on the body diagonal$=2\times 4$=8

$\therefore$ Total number of atoms =1+8= 9