Question

If $Z$ is the number of atoms in the unit cell that represents the closest packing sequence ABCABC, the number of tetrahedral voids in the unit cell is equal to:

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

Answer 1

Answer: (B)

$2Z$

As we know, number of tetrahedral voids in closed packed ccp or fcc and hcp is double the number of atoms $\left(Z\right)$ forming the main lattice. So, the number of tetrahedral voids in the unit cell is equal to $2Z$.