JEE MainChemistryCoordination Compounds
Crystal Field Theory (CFT) is unable to successfully explain the experimentally observed order of the spectrochemical series. Which of the following fundamental postulates of CFT is primarily responsible for this limitation?
Options
- AThe assumption that ligands are treated as point charges or point dipoles.
- BThe assumption that the metal-ligand bond possesses significant covalent character.
- CThe assumption that all five d-orbitals are degenerate in a free metal ion.
- DThe assumption that ligands can accept electron density into their empty -orbitals.
Correct answer
A. The assumption that ligands are treated as point charges or point dipoles.
Step-by-step solution
Crystal Field Theory (CFT) considers the metal-ligand bond to be purely ionic arising from electrostatic interactions. Ligands are treated as point charges (in case of anions) or point dipoles (in case of neutral molecules). Because of this assumption, anionic ligands should exert the greatest repulsive effect on the d-electrons of the metal ion, leading to maximum crystal field splitting. However, experimentally, anionic ligands (like halides) are found at the lower end of the spectrochemical series, acting as wea