The Columbia Encyclopedia, Sixth Edition. Columbia Encyclopedia World Factbook Columbia Gazetteer American Heritage Coll.
Isomerism is the occurrence of such compounds.
Isomerism was first recognized by J. J. Berzelius in 1827. 1 General Characteristics Isomers have the same number of atoms of each element in them and the same atomic weight but differ in other properties. Tautomers are structural isomers that readily convert from one isomeric form to another and therefore exist in equilibrium. 3 Structural Isomers Structural isomers are subdivided as chain, position, and functional group. Chain isomers occur among the alkanes .