3.0 Tautomerism

3.1 Structural requirement for tautomrism
3.2 Cause of tautomerism
3.3 Keto-enol tautomerim
3.4 Percentage Composition of Tautomeric Mixture
3.5 Triad System containing Nitrogen
3.6 Mechanism of tautomerism
3.7 Stereoisomerism
3.8 Geometrical Isomerism
3.9 Reason of Occurrence of geometrical Isomerism

It is a special type of functional isomerism in which the isomers are readily interchangeable and maintain a dynamic equilibrium with each other. Hence, the name dynamic isomerism. Both the isomers represent one and a single substance. This isomerism is caused by the oscillation of a hydrogen atom between two polyvalent atoms with necessary rearrangement of linkage.

This type of isomerism in which a substance behaves as if it has two different structures is known as tautomerism and different forms are called as tautomers. Tautomerism is also known as desmotropism (Desmos = bond, tropos = turn)