According to the valence bond theory, the metal atom or ion under the influence of ligands can use its (n-1)d, ns, np, nd orbitals for hybridization to yield a set of equivalent orbitals of definite geometry. These hybridized orbitals are allowed to overlap with ligand orbitals that can donate electron pairs for bonding. It is usually possible to predict the geometry of a complex from the knowledge of its magnetic behaviour on the basis of the valence bond theory. Consider the formation of \([Co(NH_3)_5Cl]Cl_2\) and answer the following question:

The hybridization of cobalt in the above coordination entity is :

\(d^2 sp^3\)

The given complex is \([Co(NH_3)_5Cl]Cl_2\) .

Here the central metal is cobalt (Co), and its electronic configuration is

Here, the central metal ion Co is in +3 oxidation state

We know that \(NH_3\) is a strong field ligand and will lead to the pairing of electrons while \(Cl^-\) is a weak field ligand but due to the higher number of the \(NH_3\) ligand it will dominate and cause pairing of electrons. So, the new configuration of the central metal ion will be:

So the hybridization will be \(d^2 sp^3\) and it is an outer orbital complex.