Question

Which one of the following complexes is an outer orbital complex?

विकल्प

• [Fe(CN)₆]⁴⁻

• [Mn(CN)₆]⁴⁻

• [Co(NH₃)₆]³⁺

• [Ni(NH₃)₆]²⁺

Answer 1

[Ni(NH₃)₆]²⁺

Explanation:

In [Ni(NH₃)₆]²⁺, Ni²⁺ is 3d⁸ and NH₃ is a weak-field ligand; no pairing of d-electrons occurs. The complex uses outer 4d orbitals for hybridisation (sp³d²), making it an outer orbital complex. The others have strong-field ligands (NH₃ with Co³⁺, CN⁻) that cause pairing and use inner (3d) orbitals, forming inner orbital complexes.