Nephelauxetic effect

The Nephelauxetic effect refers to the phenomenon where the presence of certain ligands in coordination complexes reduces the bond strength and the energy separation between the d-orbitals of a metal ion. This effect is commonly observed in transition metal complexes. Specifically, when a metal ion is coordinated to ligands, the electrostatic repulsion between the electron clouds of the ligands and the d-electrons of the metal is lessened.