[Co(NH3)6]Cl2 Co2+:[Ar]3d74s04p0 For this complex Δ0< P.E., so pairing of electron does not take place. sp3d2 hybridisation Total 3 unpaired electrons are present. [Co(NH3)6]Cl3 Co3+:[Ar]3d64s04p0 d2sp3 hybridisation NH3 acts as SFL because Δ0>P.E So here all electrons becomes paired.