What are the limitations of the crystal field theory ?
Although the crystal field theory explains successfully various physical properties of a complex, yet there are certain limitations of the crystal field theory, which are summarized below.
Crystal field theory explains the structures of complexes, magnetic properties, colour and electronic spectra, thermodynamic and kinetic aspects of the complexes.
However, the crystal field theory has some serious limitations or demerits. The limitations of the crystal field theory are as follows
- Crystal field theory (CFT) considers only the metal d-orbitals and s- and p- orbitals are ignored.
- This theory has not considered the covalent character in transition metal complexes.
- CFT has also not considered the π-bonding (either the M→L or L→M) in complexes.
- Crystal field theory cannot explain the relative strength of ligands as given in the spectrochemical series.
- The compounds like Cr(CO)6, Ni(CO)4 in which metal is in zero oxidation state and the ligand is neutral, have no electrostatic attraction between the metal and the ligands.