Which of the following is correct for a hexagonal crystal system?
Answer & explanation
Correct answer: option 3
| Crystal system | Edge lengths | Angles |
| Cubic | a = b = c | α = β = γ = 90° |
| Tetragonal | a = b ≠ c | α = β = γ = 90° |
| Orthorhombic | a ≠ b ≠ c | α = β = γ = 90° |
| Monoclinic | a ≠ b ≠ c | α = γ = 90° β ≠ 90° |
| Hexagonal | a = b ≠ c | α = β = 90° γ = 120° |
| Rhombohedral | a = b = c | α = β = γ ≠ 90° |
| Triclinic | a ≠ b ≠ c | α ≠ β ≠ γ ≠ 90° |