Δ0=(−0.4×nt2g)+(0.6×neg) where, n= number of electrons in nt2g and neg. CFSE of given alpha -electrons configuration are as follows a. For high spin, d6; Δ0(CFSE)=−0.4×4+0.6×2=−0.4 b. For low spin, d4; Δ0(CFSE)=−0.4×4+0.6×0=1.6 c. For low spin d5 Δ0(CFSE)=−0.4×5+0.6×0=−2.0 d. For high spin, d7 Δ0(CFSE)=−0.4×5+0.6×2=−0.8 Neglecting -ve sign (as it indicates that energy is released. Hence, maximum Δ0 (CFSE) value is shown by low spin d5 configuration.