Oxidation state of Cr in [Cr(H2O6)]+2 is +2 Electronic configuration of Cr=(Ar)184S13d5 Electronic configuration of Cr2+=(Ar)163d4 H2O is W & F ligand CFSE value =[−0.4n2g+0.6neg]Δ0+nP =[−0.4×3+0.6×1]Δ0+0 =−0.6Δ0 Oxidation state of Cr in [Cr(H2O)6]+3 is +3 Electronic configuration of Cr3+=(Ar)183d3 CFSE value =[−0.4n+2g+0.6neg]Δ0+nP =[−0.4×3+0]Δ0+0 =−1.2Δ0 CFSE does not effect colour rather 0 value can change colour.