The crystal field stabilisation energy (CFSE) and magnetic moment (spin - only) of CO2+ octahedral aqua complex are −0.8Δ0 and 3.87BM respectively.
CFSE =[(e−in t2g)×(−0.4)+(e−in eg)×0.6]Δ0 =[5×−0.4+2×0.6]Δ0 =−0.8Δ0 Magnetic moment (spin only) can be calculated as: μ=√n(n+2) (where, µ = spin only magnetic moment and n = number of unpaired electrons = 3 =√3(3+2)=√15=3.87BM