Crystal Field Splitting
An ionic theory which is an offshoot of electrostatic theory. It ignores all covalent bonding effects. It was developed by Hans Bethe in 1929 by applying group theory and quantum mechanics to electrostatic theory. It was further developed by physicists during the 1930s and 1940s. It can be used to predict chemical properties, kinetic properties, reaction mechanisms, magnetic and spectral properties, and thermodynamic data. It cannot, however, be applied to sulfides, since sulfide forms mainly covalent bonds.
A splitting of energy levels ("crystal field splitting") occurs because the orientation of the d orbital wavefunctions will increase an electron's energy when the orbital is located in a region of high electron density, and lower it when the reverse is true. In crystals, the 
,
,
,
,
orbitals split up as depicted below, depending on their cation's coordination. The total energy splitting 
is termed the crystal field stabilization energy. may be estimated from
,,,, orbitals split up as depicted below, depending on their cation's coordination. The total energy splitting is termed the crystal field stabilization energy. may be estimated from
where r is the radius of the d orbital and R is the metal-ligand internuclear distance. A large crystal field splitting energy is provided by ligands with high negative charge and small radius, and by metal cations with a large oxidation number.
Let 
denote the cubic splitting, 
the tetrahedral splitting, and 
the octahedral splitting. Then
denote the cubic splitting, the tetrahedral splitting, and the octahedral splitting. Then
To continue click on the link below:
No comments