Chemistry - Coordination Chemistry Question with Solution | TestHub

The crystal field splitting (CFS) depends on the ligand strength and oxidation state. NH₃ is a stronger field ligand than Cl⁻. Co(II) has a lower oxidation state than Co(III). For $[\mathrm{Co}({\mathrm{NH}}_3{)}_6{]}^{2+}$, the Co(II) is in a weak field. For $[{\mathrm{MnCl}}_4{]}^{2-}$, Mn(II) is in a tetrahedral field, which has smaller splitting than octahedral. $[\mathrm{Co}({\mathrm{NH}}_3{)}_5\mathrm{Cl}{]}^{2+}$ involves Co(III), which has a higher splitting. Thus, $[\mathrm{Co}({\mathrm{NH}}_3{)}_6{]}^{2+}$ has stronger splitting than $[{\mathrm{MnCl}}_4{]}^{2-}$.