Symmetry Lab › D∞h › Mercury(I) chloride (calomel)
Hg₂Cl₂ Mercury(I) chloride (calomel)
Linear · point group D∞h · order ∞
- Point group
- D∞h — A linear molecule with a centre of inversion: the C∞ axis, the planes containing it, a perpendicular mirror plane and an infinite number of perpendicular C2 axes.
- Order
- ∞
- Operations
- E, 2C∞, ∞σᵥ, i, 2S∞, ∞C₂
- Shape
- Linear
- Atoms
- 4 (Cl × 2, Hg × 2)
Symmetry elements of Hg₂Cl₂
- C∞ — the molecular axis: any rotation leaves the molecule unchanged
- σᵥ (one of ∞) — any plane containing the axis
- σᵥ (another) — any plane containing the axis
- i — centre of inversion
- σh — perpendicular to the axis, through the centre
- C₂ (one of ∞) — any line through the centre perpendicular to the axis
- C₂ (another) — same, at right angles
- S∞ — any rotation about the axis, then reflect in σh
Structure
- Hg–Hg 2.52 Å, Hg–Cl 2.49 Å
- Cl–Hg–Hg–Cl linear
- The Hg₂²⁺ ion: a metal–metal bond in a main-group-like salt
