Question

The number of octahedral sites in a cubical close packed array of $N$ spheres is :

• A. $\frac{N}{2}$
• B. 2N
• C. N
• D. 4N

Answer 1

Answer: (C)

N

The ratio of spheres and octahedral void in ccp is $1:1$. Therefore, for N spheres, the number of octahedral voids will be N.

The number of octahedral sites in a cubical close packed array of N spheres is N.

For example, a ccp lattice contains $4$ atoms per unit cell. It has $4$ octahedral voids and $8$ tetrahedral voids.