Question

Explain hydrate isomerism and linkage isomerism with suitable examples?

Answer 1

Isomerism is the phenomena in which more than one compound has the same chemical formula but different chemical components, i.e. the same number of atoms are present.

Complete answer:

Isomerism, having the same number of atoms but arranged in different order are called isomers and the phenomena is known as isomerism. There are many different types of isomerism present named as:
1. Ionization isomerism
2. Coordination isomerism
3. Linkage isomerism
4. Hydrate isomerism
Now, talk about hydrate isomerism. They are also called as solvent isomers and they differ in the number of water molecules but they have the same composition. In this one ion is directly attached to central metal but remaining is not. And they are called hydrated because when we talk about water we use the word hydrated.
Example: $\left[ {Cr({H_2}{O_6})} \right]C{l_3}\;and\;[Cr({H_2}O)Cl]C{l_2}.{H_2}O$ are hydrated isomerisms and water is present in both compounds.
Linkage isomers are defined as the same composition but differing in their connectivity to metals. The ligands which give linkage isomers are:
Thiocyanate, $SC{N^ - }$
Nitrite, $NO_2^ -$
Linkage isomerism of dimethyl sulfoxide is observed in the NMR spectrum. Let’s consider one example of linkage isomerism is:
Violet colored ${\left[ {{{(N{H_3})}_5}Co - SCN} \right]^{2 + }}$

Note: Hydrate isomerism is also called as solvent isomerism due to presence of water in it and they are similar in composition but different in arrangements. Linkage isomerism has the same molecular formula but their attachment to metals is different.