Question

\([Co (NH_3)_6]^{3+}\) and \([CoF_6]^{3+}\) are respectively known as 

(1) Spin free Complex, Spin paired Complex 

(2) Spin paired Complex, Spin free Complex 

(3) Outer orbital Complex, Inner orbital Complex 

(4) Inner orbital Complex, Spin paired Complex

Answer 1

(2) Spin paired Complex, Spin free Complex 

\([Co (NH_3)_6]^{3+}\)

\(Co^{3+}\) (strong field ligand) \(\Rightarrow 3d ^6 (t^6_{2g},e^0 _g),\)

Hybridisation : \(d^2sp^3\)

Inner obital complex(spin paired complex) 

Pairing will take place.

\([CoF_6]^{3+}\)

\(Co ^{3+}\) (weak field ligand) \(\Rightarrow 3d^6 (t^4 _{2g},e^2 _g)\)

Hybridisation : \(sp^3d^2\)

Outer orbital complex (spin free complex) no pairing will take place