Question

The density of CaF2 (fluorite structure) is 3.18 g/cm3. The length of the side of the unit cell is

Answer 1

4466 this is the answer

Answer 2

Cubic crystal or a substance is made up of space lattice. In the space lattice, the substance is made up of packing of a number of unit cells.

$Density\quad of\quad unit\quad cell\quad =\quad \frac { Mass\quad of\quad unit\quad cell }{ Volume\quad of\quad unit\quad cell }$

$=\quad \frac { Number\quad of\quad cells\quad \times \quad Mass }{ { a }^{ 3 } }$

The number of unit cells in ${ CaF }_{ 2 }$ is 4.

Accordingly,

$Side\quad (a)\quad =\quad \sqrt [ 3 ]{ \frac { 4\quad \times \quad 78.7 }{ 3.18 } }$

$=\quad \sqrt [ 3 ]{ 98.99 }$

$Side\quad (a)\quad =\quad 4.62$