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

The question relates to the number of body-centered unit cells in the 14 types of Bravais lattices. Bravais lattices are a foundational concept in crystallography, describing the distinct lattice structures that can be formed by points (representing atoms, ions, or molecules) in three-dimensional space.

To determine the correct answer, we need to examine the various types of Bravais lattices and identify those that are body-centered. A body-centered cubic lattice has atoms at all eight corners of the cube and a single atom in the cube's center.

The 14 types of Bravais lattices are categorized into 7 crystal systems. The ones that include body-centered unit cells are:

1. Cubic System: Includes a Body-Centered Cubic (bcc) lattice.
2. Tetragonal System: Includes a Body-Centered Tetragonal lattice.
3. Orthorhombic System: Includes a Body-Centered Orthorhombic lattice.

Thus, there are exactly three Bravais lattices that are body-centered:

• Body-Centered Cubic (bcc) in the Cubic system
• Body-Centered Tetragonal in the Tetragonal system
• Body-Centered Orthorhombic in the Orthorhombic system

Hence, the correct answer is 3, which matches the option provided as the answer.

This detailed understanding of crystallography is essential for exams related to chemistry and materials science, as these concepts frequently appear in questions regarding crystal structures and properties of materials.