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1 . Introduction

Proposed by
H. Bethe & Van Bleck(1935)


H. Bethe


 Van Bleck

Used for 
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
  1. The bond between the metal and the ligands is 100% ionic.
  2. In the coordination compound the charges are present in metal ions and ligands.
  3. 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.
  4. The interaction between the metal ion and ligands is attractive while the interaction between the electrons of metal and the ligands is repulsive.
  5. The d orbital in a free metal will have the same energy. In the presence of ligands, the degenerate d orbital undergo splitting.
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