Question

Compounds of transition metals are generally coloured. Give reason.

Hint:

Transition metal compounds are colored because of d-d transitions, where electrons absorb visible light and move between split d-orbitals.

Answer 1

The coloration of transition metal compounds typically arises from d-d transitions. Within these compounds, ligand fields induce a splitting of the d-orbitals into two distinct energy levels. Electron excitation from lower to higher energy d-orbitals occurs when they absorb visible light. The absorbed light's wavelength is directly proportional to the energy differential between the split d-orbitals; the transmitted light dictates the compound's observed color. This effect is prevalent in transition metal complexes, especially those with partially filled d-orbitals. Ligand type and the metal's oxidation state also influence the resulting color.