For the same central metal ion, the CFSE increases with increase in strength of the ligand. The order of strength of ligand is given by the spectrochemical series: I−<Br−<SCN−<Cl−<S2−<F−<OH−
<C2O42−<H2O<NCS−<EDTA4−<NH3<en<CN−<CO
Thus, the order of CFSE of given complexes will be :