Question

The magnitude of CFSE (Crystal Field Splitting Energy, $\Delta_{0}$) cab be related to the configuration of d-orbitals in a coordination entity as

• A. If $\Delta_{0} < P,$ the configurations is ${t_{2}}_{g}^{3}e_{g}^{1} =$weak field ligand and high spin complex
• B. If $\Delta_{0} > P,$ the configurations is ${t_{2}}_{g}^{3}e_{g}^{1} =$strong filed ligand and low spin complex
• C. If $\Delta_{0} > P,$ the configurations is ${t_{2}}_{g}^{4}e_{g}^{0} =$strong field ligand and high spin complex
• D. If $\Delta_{0} > P,$ the configurations is ${t_{2}}_{g}^{4}e_{g}^{0} =$strong field ligand and high spin complex.

Answer 1

Answer: (A)

If $\Delta_{0} < P,$ the configurations is ${t_{2}}_{g}^{3}e_{g}^{1} =$weak field ligand and high spin complex

Answer 2

If CFSE ($\Delta_{0}$) < P (Energy required for pairing), the electrons do not pair up and fourth electron goes to $e_{g}$of higher energy. Hence, high spin complex is formed. Pairing of electrons does not take place in case of weak field ligands.