How many space lattices are obtainable from the different crystal systems?

The relation between axis and angles $a \neq b \neq c$ and $\alpha = \gamma = 90^{\circ}, \beta \neq 90^{\circ}$ corresponds to which crystal system?

Which of the following does $NOT$ have a triclinic structure?

Intercepts of a plane in a crystal are given by $a$, $b/2$, $3c$ in a simple cubic unit cell. The Miller indices are:

Which of the following crystal systems exists only as a primitive Bravais lattice?

$SrO$ 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?