Explain the differences in values of the ligand field splittings (Delta = DeltaO or DeltaT for the cobalt complexes below): [Co(NH3)6]3+ ----> Delta = 22,900 cm-1, [Co(H20)6]3+ -----> Delta = 18,200 cm-1, [Co(NH3)6]2+ -----> Delta = 10,200 cm-1 [Co(NH3)4]2+ ----> Delta = 5,900 cm-1