Question

A compound AB has a simple cubic structure and has molecular mass $99$. Its density is $3.4$ $g/c{m}^3$. What will be the edge length of the unit cell?

Answer 1

$Z=1$

$M_A=99$

$\rho =3.4$ $g/c{m}^3$

$a=?$

$\rho =\frac{Z\times M_A}{N_A\times a^3}$

$\Rightarrow 3.4=\frac{1\times 99}{6.023\times {10}^{23}\times a^3}$

$\Rightarrow a^3=52.34\times {10}^{-24}$ $c{m}^3$

$\Rightarrow a=1.73\times {10}^{-8}$ $cm$

$\Rightarrow a=1.73\mathring{A}$