Question

The crystal system of a compound with unit cell dimensions $a=0.387nm$, $b=0.387nm$ and $c=0.504nm$ and $\alpha =\beta ={90}^{\circ }$ and $={120}^{\circ }$ is :

• A. cubic
• B. hexagonal
• C. orthorhombic
• D. rhomobohedral

Answer 1

The correct option is B hexagonal


Unit cell dimensions of hexagonal unit cell are $a=b\ne c$ and $\alpha =\beta ={90}^{\circ }$ and $\gamma ={120}^{\circ }$.
Examples are $ZnO,CdS$