Question

The unit cell with crystallographic dimensions $a\ne b\ne c,$ $\alpha =\gamma ={90}^{\circ },\beta \ne {90}^{\circ }$ is

• A. Cubic
• B. Tetragonal
• C. Monoclinic
• D. Hexagonal

Answer 1

The correct option is C Monoclinic

The dimesions for cubic geometry are $a=b=c,$ $\alpha =\beta =\gamma ={90}^{\circ }$.
The dimesions for tetragonal geometry are $a=b\ne c,$ $\alpha =\beta =\gamma ={90}^{\circ }$.
The dimesions for monoclinic geometry are $a\ne b\ne c,$ $\alpha =\gamma ={90}^{\circ },\beta \ne {90}^{\circ }$.
The dimesions for hexagonal geometry are $a=b\ne c,$ $\alpha =\beta ={90}^{\circ },=\gamma ={120}^{\circ }$.