$\mathrm{Co}^{3+}(\text { strong field ligand }) \Rightarrow 3 \mathrm{~d}^6\left(\mathrm{t}_{2 \mathrm{~g}}^6, \mathrm{e}_{\mathrm{g}}^0\right),$

Hybridisation : $d^2 \mathrm{sp}^3$

Inner obital complex(spin paired complex)

Pairing will take place.

$\left[\mathrm{CoF}_6\right]^{3-}$

$\mathrm{Co}^{3+}$ (weak field ligand) $\Rightarrow 3 \mathrm{~d}^6\left(\mathrm{t}_{2 \mathrm{~g}}^4, \mathrm{e}_{\mathrm{g}}^2\right)$

Hybridisation : $\mathrm{sp}^3 \mathrm{~d}^2$

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