Proposed by H. Bethe & Van Bleck(1935) H. Bethe  Van Bleck Used fo r  Firstly used for the   explanation of color and the magnetic properties of crystalline solid. In 1951, several theoretical chemists working independently used crystal field theory to interpret the spectra of transition metal complexes. Principle-  it is based on the principle of electrostatic theory, "the bond energy between two oppositely charged ions q and q' placed at a distance between 'r' with each other is given by the equation  Salient features of CFT The bond between the metal and the ligands is 100% ionic. In the coordination compound the charges are present in metal ions and ligands. Metal act as a positive charge whereas the negative charge is due to the ligands as the point charge in anion or the point dipole in the neutral ligands like water and ammonia. The interaction between the metal ion and ligands is attractive wh...

CRYSTAL FIELD SPLITTING   Before the study of this topic we have first know about the spatial orientation of d- orbitals. The five d orbitals can be designated as follow The first three orbital are oriented in between the XY, YZ, ZX axes respectively and these three orbital are called t 2g or d E  and the rest two orbitals are oriented along the XY and Z axes respectively and are known as e g  or d r. Now we will discuss about our topic which is  CRYSTAL FIELD SPLITTING,   in the absence of any ligands or in the case of free metal ion, all the five d-orbitals have the same energy and the orbitals having the  same energy are called degenerate orbitals. However in the approach of the ligands, the orbital electrons will be repelled by the lone pair (or negative charge) of the ligands. The repulsion will raise the energy of d - orbitals, the energy of each orbital will increase by the same amount, due to spherical field or s...