Crystal field splitting template

d-orbital splitting diagrams for octahedral (t₂g/eg, Δo), tetrahedral (e/t₂, Δt ≈ 4/9 Δo) and square planar complexes, with the barycentre and example complexes.

What the template shows

• How the ligand arrangement splits the five d orbitals of a metal ion (energies in units of Δo, to scale)
• Ligands on ±x, ±y, ±z point at the eg lobes
• free ion
• dxy, dxz, dyz
• Inverted pattern and smaller: Δt ≈ 4/9 Δo; almost always high spin
• e.g. [CoCl₄]²⁻, [NiCl₄]²⁻
• Square planar
• Remove the two z ligands: z orbitals fall, dx²−y² is left high; typical of d⁸ ions
• dxz, dyz
• e.g. [Ni(CN)₄]²⁻, [PtCl₄]²⁻, cisplatin
• Octahedral: t₂g at −0.4Δo and eg at +0.6Δo; the weighted average stays at the barycentre (3 × −0.4 + 2 × 0.6 = 0).
• Tetrahedral: four ligands, none pointing at a d lobe, so the splitting is inverted (e below t₂) and smaller, Δt ≈ 4/9 Δo.
• Square planar: the strongly destabilised dx²−y² stays empty for d⁸ ions (Ni²⁺, Pd²⁺, Pt²⁺, Au³⁺), which favours this geometry. Levels from angular overlap (12.28, 2.28, −4.28, −5.14 Dq); the place of dz² varies with the ligands.
• Δ grows along the spectrochemical series I⁻ < Br⁻ < Cl⁻ < F⁻ < OH⁻ < H₂O < NH₃ < en < NO₂⁻ < CN⁻ < CO, and with metal charge and row (3d < 4d < 5d).
• Every part of this figure is editable · sources on the template card

Drawn with 258 shapes – every one editable in MolDraw.

Sources

• Housecroft & Sharpe, Inorganic Chemistry, 5th ed., Pearson 2018, ch. 20 Textbook
• Miessler, Fischer & Tarr, Inorganic Chemistry, 5th ed., Pearson 2014, ch. 10 Textbook