Nuclear Magnetic Resonance Spectroscopy

Crystal field splitting in tetragonal complexes:

If two trans- ligands in an octahedral complex are moved either towards or away from the central metal ion, the resulting complex is called tetragonally distorted. If the two ligands are brought closer to the central metal ion, the octahedron tends to flatten. This is called flattening of the octahedron in which two trans M-L bonds are shortened while other four M-L bonds are lengthened.

In case of tetragonal geometry, the energy of dx^2-y^2 repulsion, although the energy of the dx^2-y^2 is raised more due to greater repulsion. On the other hand, the energy of dxz and dyz are lowered whereas the energy of dxy is slightly more (see figure).