The crystal field model does not consider the covalent character of bonding between ligands and the central atom, which is a weakness of the model.

The CFT assumes ligands as point charges, leading to the expectation that anionic ligands would have the highest splitting effect. However, this contradicts the observed positioning of anionic ligands at the low end of the spectrochemical series.

The color of transition metal complexes is complementary to the absorbed light; for example, if green light is absorbed, the complex appears red. The wide range of colors arises from the removal of specific wavelengths from white light as it ...

The ‘g’ subscript is used for complexes with a center of symmetry, which octahedral and square planar complexes possess. Tetrahedral complexes lack symmetry, so the ‘g’ subscript is not used in their energy level designations.

The orbital splitting energies (∆ₜ) in tetrahedral coordination entities are not large enough to force electron pairing, resulting in low spin configurations. The relationship is given by ∆ₜ = (4/9) ∆₀ for the same metal, ligands, and metal-ligand distances.

In [PtCl₆]²⁻, Pt has a coordination number of 6, and in [Ni(NH₃)₄]²⁺, Ni has a coordination number of 4. Similarly, [Fe(C₂O₄)₃]₃³⁻ and [Co(en)₃]³⁺ both have a coordination number of 6.

The coordination number (CN) of a metal ion in a complex is the count of ligand donor atoms directly bonded to the metal. It determines the spatial arrangement around the central metal ion.

Ambidentate ligands, like NO₂⁻ and SCN⁻ ions, have two different donor atoms. NO₂⁻ can coordinate through nitrogen or oxygen, while SCN⁻ can coordinate through sulfur or nitrogen, offering flexibility in metal binding.

Chelate ligands, like EDTA⁴⁻, use two or more donor atoms simultaneously to bind a metal ion, forming more stable complexes than those with unidentate ligands. The denticity of the ligand is the number of such ligating groups.

Unidentate ligands, like Cl⁻ or H₂O, bind through a single donor atom. Didentate ligands, such as ethane-1,2-diamine or oxalate, bind through two donor atoms. Polydentate ligands, like N(CH₂CH₂NH₂)₃, have several donor atoms in a single ligand.