For a simple cubic crystal,the edge length is expressed as:

Which of the following crystals has the unit cell such that $a=b \neq c$ and $\alpha=\beta=90^{\circ}$,$\gamma=120^{\circ}$?

Which of the following is correct regarding crystal systems?

$SrO$ has a $NaCl$ structure. If the lattice constant $a = 0.514 \ nm$ and the ionic radius of $Sr^{2+} = 0.113 \ nm$,what is the radius of the $O^{2-}$ ion?

What is the total number of different types of unit cells in a tetragonal crystal system?

The triclinic unit cell has the following parameters: