Question

The correct option for the number of body centred unit cells in all 14 types of Bravais lattice unit cells is

• A. 3
• B. 7
• C. 5
• D. 2

Answer 1

The Correct Option is A

To solve the problem of identifying the number of body-centered unit cells in the 14 types of Bravais lattice, let's first understand the concept of Bravais lattices and types of unit cells.

The 14 Bravais lattices in crystallography are the distinct lattice structures which emerge from considering the 7 different crystal systems with 3 types of cell-centered conditions (primitive, body-centered, face-centered). These lattices are named after the French physicist Auguste Bravais.

Here is a breakdown of the Bravais lattices based on the type of centering:

• Primitive (P): Lattice points only at the corners of the unit cell.
• Body-Centered (I): Lattice points at the corners and one additional point at the center of the unit cell.
• Face-Centered (F): Lattice points at the corners and one point at the center of each face of the unit cell.
• Base-Centered (C): Lattice points at the corners and one point at the center of each pair of parallel faces.

Among these, the body-centered lattices include:

1. Body-Centered Cubic (bcc)
2. Body-Centered Tetragonal (bct)
3. Body-Centered Orthorhombic (bco)

Therefore, there are a total of 3 body-centered unit cell types in the 14 Bravais lattices: cubic, tetragonal, and orthorhombic body-centered lattices. Hence, the correct answer is 3.

Given the options and explanation, the answer is comprehensively determined with understanding the nature of Bravais lattices.