Coordination Compounds Simulator

Coordination Number & Geometry

CN=2: Linear, CN=4: Tetrahedral/Square Planar, CN=6: Octahedral, CN=8: Cubic

Geometry depends on ligand size and metal ion

Crystal Field Splitting

Δ₀ = energy gap between t₂g and e_g

Strong field ligands: CN⁻, CO, NH₃ (low spin)

Weak field ligands: H₂O, F⁻, Cl⁻ (high spin)

Oxidation State

OS = charge on complex - sum of ligand charges

Example: [Fe(CN)₆]⁴⁻: OS = 4 - 6(-1) = +2

Higher OS → larger Δ₀

Ligands

Monodentate: H₂O, NH₃, Cl⁻

Bidentate: en (ethylenediamine), oxalate

Polydentate: EDTA (hexadentate)

🧠 Spectrochemical Series

I⁻ < Br⁻ < Cl⁻ < F⁻ < H₂O < NH₃ < en < CN⁻ < CO
Left = weak field (high spin)
Right = strong field (low spin)

🧠 Coordination Number Rules

CN = number of sigma bonds
Not number of ligands!
EDTA: 1 ligand, 6 bonds, CN=6

🧠 Geometry by CN

CN=2: Linear
CN=4: Tetrahedral or Square Planar
CN=6: Octahedral
CN=8: Cubic

🧠 Crystal Field Splitting

Δ₀ increases with:
1. Higher oxidation state
2. Stronger field ligands
3. Later transition metals

❌ Confusing coordination number

CN = number of sigma bonds, not number of ligands. EDTA forms 6 bonds but is 1 ligand. CN=6, not 1.

❌ Wrong oxidation state calculation

Always: OS + sum(ligand charges) = complex charge. Don't forget the overall charge bracket.

❌ Mixing up spectrochemical series

I⁻ < Br⁻ < Cl⁻ < F⁻ < H₂O < NH₃ < en < CN⁻ < CO. Stronger field = larger Δ = more likely low spin.

❌ Forgetting d⁹ exception

d⁹ (Cu²⁺) always shows Jahn-Teller distortion in octahedral. d⁴ high spin also distorts. JEE Advanced asks this regularly.