Question

Which of the following is/are correct for a diamond structure?

• A. There are 6 atoms per unit cell.
• B. Carbon particles occupy half of octahedral voids and occupy hcp sites
• C. Carbon particles occupy half of tetrahedral voids and occupy fcc sites
• D. There are 8 atoms per unit cell.

Answer 1

Answer: (C), (D)

There are 8 atoms per unit cell.

In a diamond structure :
Carbon particles occupy half of tetrahedral voids and occupy fcc sites.
There are 8 atoms per unit cell.
The structure of diamond is identical to zinc blende $\left(ZnS\right)$ structure.
Here,
$\frac{\sqrt{3}a}{4}=2r_c$
Here,
$a$ is the edge cell length.
$r$ is the radius of carbon atom.