Which of the following complex is an outer orbital complex? — Coordination Compounds Chemistry Question

💡 Solution & Explanation

Step 1: Outer orbital complexes utilize outer d-orbitals (sp^3d^2 hybridization) instead of inner d-orbitals (d^2sp^3 hybridization) for coordination. Step 2: For Ni^2+ (3d^8) in an octahedral field, the d-orbitals are filled as t_2g^6 e_g^2. Since two d-orbitals in the inner 3d shell are occupied, it cannot accommodate the d^2sp^3 configuration. Step 3: Therefore, it must use the 4d orbitals, resulting in sp^3d^2 hybridization (outer orbital complex). Thus, [Ni(NH3)6]^2+ is an outer orbital complex, matching option (a).