Question

For a crystal system, $a=b=c$ and $\alpha =\beta =\gamma \ne {90}^0$ is :

• A. Tetragonal
• B. Hexagonal
• C. Rhombohendral
• D. Monoclinic

Answer 1

Answer: (C)

Rhombohendral

A) For Tetragonal crystal system; a = b ≠ c and α = β = γ = 90〫

B) For Hexagonal crystal system; a = b ≠ c and α = β = 90, γ = 120〫

C) For Rhombohedral crystal system; a = b = c and α = β = γ ≠ 90〫

D) For Monoclinic crystal system; a ≠ b ≠ c and α = γ = 90, β ≠ 90〫

The given unit cell dimensions and angles matches with that of Rhombohedral crystal system.

Hence, option C is correct.