- 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 (S, O × 3)
Symmetry elements of SO₃
- C₃ — perpendicular to the plane of three O atoms
- C₂ (1) — along one S–O bond
- C₂ (2) — along one S–O bond
- C₂ (3) — along one S–O bond
- σh — the plane of the three O 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
- S=O 1.420 Å
- O–S–O 120°
- No lone pair on S
