Question

How many atoms are in a bcc unit cell?

Answer 1

In a body-centered cubic (BCC) unit cell, there are two atoms. One atom is located at the center of the cube, and the other atom is positioned at each of the eight corners of the cube. Each corner atom is shared between eight adjacent unit cells, so it contributes only $(\frac {1}{8})$th to the total count.
Thus, the total number of atoms in a BCC unit cell is:
1 (center atom) + $\frac{1}{8}$ x 8 (corner atoms) = 2 atoms.