Chemistry - Solid State Question with Solution | TestHub

The packing efficiency of a face-centered cubic (fcc) unit cell is $74\%$.

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

Given the total volume of the unit cell is $V=6.4\times 10^{-23}{\text{cm}}^3$.

Void volume $=0.26\times V$

Void volume $=0.26\times 6.4\times 10^{-23}{\text{cm}}^3=1.664\times 10^{-23}{\text{cm}}^3$

Answer: $1.664\times 10^{-23}{\text{cm}}^3$