Question

For the complex ion of $\left[Co\right(N{H}_3{)}_6{]}^{3+}$:
(i) State the hybridisation of the complex.
(ii) State the magnetic nature of the complex.

Answer 1

In $\left[Co\right(N{H}_3{)}_6{]}^{3+}$ the oxidation state of cobalt is $+3$.Ammonia is a strong field ligand so it pair up 4 unpaired electron and free up 2 $3-d$ orbitals. These $3-d$ orbitals are involved in hybridisation with one $4S$ and three $4P$ orbitals forming an inner orbital complex, so hybridisation of $\left[Co\right(N{H}_3{)}_6{]}^{3+}$ is $d^{2}s{p}^3$

Since it has no unpaired electrons, $\left[Co\right(N{H}_3{)}_6{]}^{3+}$ is diamagnetic.