$\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$ has magnetic moment of a single unpaired electron whereas $\left[\mathrm{FeF}_6\right]^{3-}$ has a magnetic moment of five unpaired electrons. $\left[\mathrm{CoF}_6\right]^{3-}$ is paramagnetic with four unpaired electrons while $\left[\mathrm{Co}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^3$ is diamagnetic. This anomaly is explained by valence bond theory in terms of formation of inner and outer orbital coordination entities. $\left[\mathrm{Co}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-}$ is an inner orbital complexes having $d^2 s p^3$ hybridization.