which varies according to the number and nature of the ligands. If the symmetry of the complex is lower than octahedral, the e_g and t_2g levels can split further. For example, the t_2g and e_g sets split further in trans-MLL.

Ligand strength has the following order for these electron donors:
:weak: iodine < bromine < fluorine < acetate < oxalate < water < pyridine < cyanide :strong