For the same metal, the same
ligands and metal-ligand distances, it can
be shown that Dt = (4/9) D0 Consequently,
the orbital splitting energies are not
sufficiently large for forcing pairing and,
therefore, low spin configurations are rarely
observed The ‘g’ subscript is used for the
octahedral and square planar complexes
which have centre of symmetry Since
tetrahedral complexes lack symmetry, ‘g’
subscript is not used with energy levels