Symmetry Lab › D6h › Bis(benzene)chromium
Cr(C₆H₆)₂ Bis(benzene)chromium
Sandwich, eclipsed rings · point group D6h · order 24
- Point group
- D6h — A C6 principal axis, 6 perpendicular C2 axes and a horizontal mirror plane; these also give 6 vertical planes and a centre of inversion.
- Order
- 24
- Operations
- E, 2C₆, 2C₃, C₂, 3C₂′, 3C₂″, i, 2S₃, 2S₆, σh, 3σd, 3σᵥ
- Shape
- Sandwich, eclipsed rings
- Atoms
- 25 (Cr, C × 12, H × 12)
Symmetry elements of Cr(C₆H₆)₂
- C₆ — through the metal and both ring centres
- C₂′ (1) — through two opposite carbons of each ring
- C₂′ (2) — through two opposite carbons of each ring
- C₂′ (3) — through two opposite carbons of each ring
- C₂″ (1) — through two opposite C–C bond midpoints of each ring
- C₂″ (2) — through two opposite C–C bond midpoints of each ring
- C₂″ (3) — through two opposite C–C bond midpoints of each ring
- i — centre of inversion
- σh — the plane of the molecule
- σᵥ (1) — contains the C₆ axis; through two opposite carbons of each ring
- σᵥ (2) — contains the C₆ axis; through two opposite carbons of each ring
- σᵥ (3) — contains the C₆ axis; through two opposite carbons of each ring
- σd (1) — contains the C₆ axis; through two opposite C–C bond midpoints of each ring
- σd (2) — contains the C₆ axis; through two opposite C–C bond midpoints of each ring
- σd (3) — contains the C₆ axis; through two opposite C–C bond midpoints of each ring
- S₆ — rotate 60°, then reflect in σh
- S₃ — rotate 120°, then reflect in σh
Structure
- Cr–C 2.15 Å, C–C 1.42 Å
- Two eclipsed benzene rings
- An 18-electron sandwich, like ferrocene
