Question

Tetragonal crystal system has which of the following unit cell dimensions?

• A. $a=b=c$ and $\alpha =\beta =\gamma ={90}^{\circ }$
• B. $a=b\ne c$ and $\alpha =\beta =\gamma ={90}^{\circ }$
• C. $a\ne b\ne c$ and $\alpha =\beta =\gamma ={90}^{\circ }$
• D. $a=b\ne c$ and $\alpha =\beta ={90}^{\circ },\gamma ={120}^{\circ }$

Answer 1

The correct option is B $a=b\ne c$ and $\alpha =\beta =\gamma ={90}^{\circ }$

Tetragonal crystal system has the unit cell dimensions as $a=b\ne c,\alpha =\beta =\gamma ={90}^{\circ }$.
Thus, two edge lengths are equal and all the bond angles are equal. They are equal to ${90}^0$.