The density of diamond is 3.51 g/cc. Calculate $\text{C}-\text{C}$ bond length in diamond.

Given that ${\left[\frac{96}{\text{3.51}\times \text{6.023}\times 10^{23}}\right]}^{1/3}$  is $\text{3.56}\times 10^{-8}$

The packing efficiency of the face centered cubic (FCC), body centered cubic (BCC) and simple/primitive cubic (PC) lattices follows the order

Based on the nature of intermolecular forces, classify the following solid:

${\mathrm{SiO}}_2$

The number of network solids and ionic solids in the list given below is respectively

${\mathrm{H}}_2\mathrm{O}\left(\mathrm{ice}\right), \mathrm{AlN}, \mathrm{Cu}, {\mathrm{CaF}}_2 ,\mathrm{diamond}, \mathrm{MgO}, {\mathrm{CCl}}_{4,} \mathrm{ZnS}, \mathrm{Ag}, \mathrm{NaCl}, {\mathrm{SiO}}_2$

Consider the bcc unit cells of the solids $1$ and $2$ with the position of atoms as shown below. The radius of atom $\mathrm{B}\mathrm{ }$ is twice that of atom $\mathrm{A}.$ The unit cell edge length is $50\mathrm{ }\mathrm{\%}$ more in solid $2$ than in $1$ . What is the approximate packing efficiency in solid $2$ ?

The vacant space in bcc lattice unit cell is: