Question

Determine the type of cubic lattice to which the crystal of element indicated here belongs. It has an edge length of 290 pm and a density 7.80 g cm. The Atomic mass of element= 56 amu.

Answer 1

Theoretical density of crystal $=\rho =\frac{nM}{N_A{a}^3}g/c{m}^3$

where symbols have usual meaning.

Given, $a=290pm=290\times {10}^{-10}cm$

$\rho =7.80g/c{m}^3;M=56g$

$\Rightarrow n=\frac{\rho \times N_A\times a^3}{M}=\frac{7.8\times 6.022\times {10}^{23}\times (290{)}^3\times {10}^{-30}}{56}$

$n=2$

So, it is body centered cubic (BCC) lattice.