The number of atoms per unit cell of BCC structure is

CONCEPT:

Body-Centered Cubic (BCC) Structure

• A body-centered cubic (BCC) unit cell has atoms at each of its eight corners and a single atom at the center of the cube.
• Each corner atom is shared among eight adjacent unit cells, and the center atom belongs entirely to the unit cell.

EXPLANATION:

• In a BCC unit cell:
  • There are 8 corner atoms, each shared by 8 unit cells. Therefore, the contribution of corner atoms per unit cell is ¹⁄₈ × 8 = 1 atom.
  • There is 1 atom at the center of the unit cell, which is not shared with any other unit cell. Therefore, the contribution of the center atom per unit cell is 1 atom.
• Adding these contributions together:
  • Total number of atoms per unit cell = 1 (from corners) + 1 (from center) = 2 atoms.

Therefore, the number of atoms per unit cell of BCC structure is 2.