Question

Primitive cell has ... lattice point per unit cell.

• A. One
• B. Two
• C. Three
• D. Four

Hint:

A unit cell is the smallest repeating structure of a crystal lattice, and when this unit cell has its lattice points at the corners, it is called a primitive cell and the structure can be reproduced in three dimensions to get a 3D lattice of the crystal, by translation.

Answer 1

The Correct Option is A

A primitive cell (also known as a simple cell) is a unit cell with a single lattice point, which is situated at its 3D corners. Each corner of a primitive unit cell is shared by 8 adjacent unit cells. Consequently, the total lattice point contribution from these 8 corners is:
\(8 \times \frac{1}{8} = 1\)
Therefore, a primitive cell contains only one lattice point per unit cell. Simple cubic structures are examples of primitive cells.
In contrast, body-centered and face-centered unit cells have more than one lattice point per unit cell, as they include lattice points at their centers or faces in addition to the corners.