Question

A compound mode up of element $A$ and $B$ crystallites in a cubic structure. Atoms $A$ are present on the corners as well as face-centres, whereas atom $B$ are present on the edge-centres as well as body-centre. What is the formula of the compound? Draw the structure of the unit cell.

Answer 1

Effective number of atoms of $A=\frac{1}{8}\times 8+\frac{1}{2}\times 6=4$

Effective number of atoms of $B=\frac{1}{4}\times 12+1=4$

Formula $=B_4{A}_4=BA$

In the image A is red atoms and B is purple atoms.