There are 2 atoms per unit cell in a Body-Centered Cubic (BCC) crystal structure.
Here's a breakdown of why:
-
Corner Atoms: In a BCC unit cell, there are atoms located at each of the eight corners of the cube. Each corner atom is shared by eight adjacent unit cells. Therefore, each corner atom contributes only 1/8 of its volume to a single unit cell. The total contribution from the corner atoms is (1/8) * 8 = 1 atom.
-
Body-Centered Atom: A single atom is located at the very center of the cube. This atom belongs entirely to that specific unit cell. Its contribution is 1 atom.
-
Total Atoms: To find the total number of atoms per unit cell, we add the contributions from the corner atoms and the body-centered atom: 1 (from corners) + 1 (from body center) = 2 atoms.
Therefore, a BCC unit cell contains a total of 2 atoms.
