Answer: Cubic.
- A Tetragonal
- B Orthorhombic
- C Cubic
- D Hexagonal
Correct answer: C. Cubic
Explanation: The cubic system has a = b = c and all angles α = β = γ = 90°.
The three cubic unit cells: Simple Cubic has atoms only at corners; Body-Centred adds one atom at the centre; Face-Centred adds one atom at the centre of each of the 6 faces, giving the highest packing efficiency.
Concept context
Explore the ordered world of crystalline solids: unit cells, packing, defects, and how structure determines electrical and magnetic properties.