Which crystal system allows for the existence of a primitive unit cell but not a body-centered unit cell?

A crystal may have one or more planes and one or more axes of symmetry but it possesses

Which of the following statements about amorphous solids is incorrect?

The constituent particles of a solid have

A crystal with $a = b = c$ and $\alpha = \beta = \gamma

eq 90^\circ$ belongs to which crystal system?

Lithium borohydride crystallizes in an orthorhombic system with 4 molecule per unit cell. The unit cell dimensions are $a = 6.8\mathop {\rm{A}}\limits^ \circ ,b = 4.4\mathop {\rm{A}}\limits^ \circ \;and\;c = 7.2\mathop {\rm{A}}\limits^ \circ$. If the molar mass is 21.76, then the density of crystals is :

Which crystal system is characterized by $a = b = c$ and $\alpha = \beta = \gamma = 90^\circ$?

The elements of symmetry in a crystal are :

The structure of ${\rm{N}}{{\rm{a}}_2}{\rm{O}}$ crystal is

The structure of ${\rm{N}}{{\rm{a}}_2}{\rm{O}}$ crystal is

For a crystal system $a = b = c;and;\alpha = \beta = \gamma

e 90^\circ $