Question

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

• A. \([\text{Co(NH}_3)_6]^{3+}\)
• B. \([\text{Mn(CN)}_6]^{4-}\)
• C. \([\text{Fe(CN)}_6]^{4-}\)
• D. [Ni(NH₃)₆]²+

Hint:

Weak ligands usually form outer orbital complexes.

Answer 1

The Correct Option is A

Step 1: Outer orbital complexes use sp³d² hybridisation.
Step 2: Weak field ligands like NH₃ do not cause pairing.
Step 3: [Co(NH₃)₆]³+ forms an outer orbital complex.