CFSE=(−0.4nt2g+0.6neg)Δ0
nt2g= Number of electrons in t2g orbital
neg=number of electrons in eg orbital.
Crystal Field Stabilisation Energy for the given complexes is as follows:
| (A) | [Cu(NH3)6]2+ Cu2+..3d6,t2g6eg3 | CFSE =(−6×0.4+3×0.6)Δ0 =−0.6Δ0 |
| (B) | [Ti(H2O)6]3+ Ti3+:3d1,t2g1eg0 | CFSE=−1×0.4Δ0 =−0.4Δ0 |
| (C) | [Fe(CN)6]3− Fe3+:3d5,t2g5eg0 | CFSE=−5×0.4Δ0 =−2.0Δ0 |
| (D) | [NiF6]4− Ni2+:3d8,t2g6eg2 | CFSE =(−6×0.4+2×0.6)Δ0 =−1.2Δ0 |
So the correct option is B.