Symmetry Lab › D4h › Tetracyanonickelate(II) ion
[Ni(CN)₄]²⁻ Tetracyanonickelate(II) ion
Square planar · point group D4h · order 16
- Point group
- D4h — A C4 principal axis, 4 perpendicular C2 axes and a horizontal mirror plane; these also give 4 vertical planes and a centre of inversion.
- Order
- 16
- Operations
- E, 2C₄, C₂, 2C₂′, 2C₂″, i, 2S₄, σh, 2σᵥ, 2σd
- Shape
- Square planar
- Atoms
- 9 (Ni, C × 4, N × 4)
Symmetry elements of [Ni(CN)₄]²⁻
- C₄ — perpendicular to the plane; also C₂ and S₄
- C₂′ (x) — through two opposite ligands
- C₂′ (y) — through the other two
- C₂″ (1) — in the plane, between ligands
- C₂″ (2) — in the plane, between ligands
- i — centre of inversion
- σh — the plane of the ion
- σᵥ (xz) — contains the axis and two ligands
- σᵥ (yz) — contains the axis and the other two
- σd (1) — contains the axis, between ligands
- σd (2) — contains the axis, between ligands
- S₄ — rotate 90°, then reflect in σh
Structure
- Ni–C 1.86 Å, C≡N 1.15 Å
- C–Ni–C 90° and 180°
- d⁸ metal centre; charge −2
![Tetracyanonickelate(II) ion ([Ni(CN)4]2-) — D4h symmetry elements](/molecular-symmetry/infographics/NiCN42-_TetracyanonickelateIIion_D4h.png)
Other D4h molecules
[Pt(NH₃)₄]²⁺ (N atoms shown)Tetraammineplatinum(II) ion[AuCl₄]⁻Tetrachloroaurate(III) ion[ICl₄]⁻Tetrachloroiodate(III) ion[PdCl₄]²⁻Tetrachloropalladate(II) ion[PtCl₄]²⁻Tetrachloroplatinate(II) ion[BrF₄]⁻Tetrafluorobromate(III) ionXeF₄Xenon tetrafluoridetrans-[CoCl₂(NH₃)₄]⁺trans-Tetraamminedichlorocobalt(III) (N atoms shown)C₄H₄²⁻Cyclobutadiene dianion (planar)[Pt(CN)₄]²⁻Tetracyanoplatinate(II) ion[Re₂Cl₈]²⁻Octachlorodirhenate(III) iontrans-[OsCl₂(CO)₄]trans-Dichlorotetracarbonylosmium(II)