Chemistry - Solid State Question with Solution | TestHub

The packing efficiency of an fcc unit cell is $74\%$.

The percentage of void space in an fcc unit cell is $100\%-74\%=26\%$.

Let the total volume of the unit cell be $V$.

Void volume $=0.26\times V$

Given void volume $=4.16\times 10^{-24}{\mathrm{cm}}^3$.

$0.26\times V=4.16\times 10^{-24}$

$V=\frac{4.16\times 10^{-24}}{0.26}$

$V=16\times 10^{-24}{\mathrm{cm}}^3$

$V=1.6\times 10^{-23}{\mathrm{cm}}^3$

Answer: $1.6\times 10^{-23}$