Question

Although co2+ ion appears to be stable it is easily oxidised to co3+ ion in the presence of syrong ligand why

Answer 1

CO2+ ions will be easily oxidized to CO3+ ions as the CFSE of CO3+ ions with configuration of d6 > d7 .

In the presence of ligands , the d- orbitals of metal will gets split up in 2 sets of orbitals i . e. t2g and eg. The half filled or completely filled t2g will be more stable than other configuration. It is due to the reason that it gives maximum amount of low energy of t2g orbital. Lower the energy, more will be the stabilization.