Question

How many spherical units belong to the unit cell of hcp ?

• A. 2
• B. 4
• C. 6
• D. 8

Answer 1

The correct option is C

6

A hexagonal unit cell consists of 12 units on the corners of end faces (each unit shared by 6 unit cells), 2 units at the centres of end faces (shared by 2 unit cells, and 3 units in the body.)

Hence, units per hexagonal unit cell
$=\frac{1}{6}\times 12\left(corners\right)+\frac{1}{2}\times 2\left(centresofendfaces\right)+3$