Chemistry - Solid State Question with Solution | TestHub

Packing efficiency: $$\begin{array}{rl}& \text{ P.E. }=\frac{\mathrm{z}\times \frac{4}{3}\pi {\mathrm{r}}^3}{V}=\frac{2\times \frac{4}{3}\times \pi {\left(\frac{\sqrt{3}\mathrm{a}}{4}\right)}^3}{{\mathrm{a}}^3}=\frac{\sqrt{3}\mathrm{a}}{8}=0.68\\ & \left[\because \mathrm{z}=2,\mathrm{r}=\frac{\sqrt{3}\mathrm{a}}{4},V={\mathrm{a}}^3\right]\end{array}$$ In B.C.C., $68\%$ of total volume is occupied by atoms or ions.