Question

The number of atoms in face-centered cubic and hexagonal unit cells respectively are ?

• A. 4, 6
• B. 6, 4
• C. 2, 6
• D. 1, 6

Answer 1

The correct option is A

4, 6

Number of particles constituting a face centered unit cell $=\frac{1}{8}\times 8\left(corners\right)+\frac{1}{2}\times 6\left(faces\right)=4$
Number of particles per hexagonal unit cell
$=\frac{1}{6}\times 12\left(corners\right)+\frac{1}{2}\left(faces\right)+3\left(inthebody\right)=6$