Chemistry - Solid State Question with Solution | TestHub

Key Idea : Packing fraction $=\frac{\text{ Volume occupied by atoms in a unit cell }}{\text{ Volume of the unit cell }}$ For body centred cube, Packing fraction $=\frac{2\times \frac{4}{3}\pi r^3}{{\left(\frac{4r}{\sqrt{3}}\right)}^3}=\frac{\sqrt{3}\pi }{8}=0.68$ where, edge length $a=\frac{4r}{\sqrt{3}}$ $\therefore$ Volume occupied $=68\%$ and volume vacant $=32\%$