Chemistry - Solid State Question with Solution | TestHub

In a face-centered cubic (fcc) unit cell, the total number of atoms (spheres) is $4$.

The tetrahedral voids are located on the body diagonals of the cube. There are $4$ body diagonals and each body diagonal contains $2$ tetrahedral voids.

Total number of tetrahedral voids in an fcc unit cell $=4\times 2=8$.

Number of tetrahedral holes per sphere $=\frac{8}{4}=2$.

Answer: $2$