Chemistry - Solid State Question with Solution | TestHub

In a body-centered cubic (bcc) unit cell, the particles touch each other along the body diagonal.

The length of the body diagonal of a cube with edge length $a$ is $\sqrt{3}a$.

Since the particles at the corners touch the particle at the body center, the body diagonal is equal to $4r$, where $r$ is the radius of the particle.

$4r=\sqrt{3}a$

$r=\frac{\sqrt{3}a}{4}$

Answer: $r=\sqrt{3}a/4$