Symmetry Lab › D3h › Aluminium chloride (monomer)
AlCl₃ Aluminium chloride (monomer)
Trigonal planar · point group D3h · order 12
- Point group
- D3h — A C3 principal axis, 3 perpendicular C2 axes and a horizontal mirror plane; these also give 3 vertical planes.
- Order
- 12
- Operations
- E, 2C₃, 3C₂, σh, 2S₃, 3σᵥ
- Shape
- Trigonal planar
- Atoms
- 4 (Al, Cl × 3)
Symmetry elements of AlCl₃
- C₃ — perpendicular to the plane of three Cl atoms
- C₂ (1) — along one Al–Cl bond
- C₂ (2) — along one Al–Cl bond
- C₂ (3) — along one Al–Cl bond
- σh — the plane of the three Cl atoms
- σᵥ (1) — contains the C₃ axis and one bond
- σᵥ (2) — contains the C₃ axis and one bond
- σᵥ (3) — contains the C₃ axis and one bond
- S₃ — rotate 120°, then reflect in σh
Structure
- Al–Cl 2.06 Å
- Cl–Al–Cl 120°
- No lone pair on Al; electron-deficient
