Crystal field splitting is the difference in energy between d orbitals of ligands. Crystal field splitting number is denoted by the capital Greek letter Δ. Crystal field splitting explains the difference in color between two similar metal-ligand complexes.
The splitting of fivefold degenerate d orbitals of the metal ion into two levels in a tetrahedral crystal field is the representation of two sets of orbitals as Td. The electrons in dx2-y2 and dz2 orbitals are less repelled by the ligands than the electrons present in dxy, dyz, and dxz orbitals.
There are the following factors that affect the crystal field splitting. These are the nature of ligands, coordination number, arrangement of ligand, size of a metal atom, charge on the metal atom, size of ligands, electronegativity, and interatomic distance.
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