Isomerism

Isomers are compounds with the same molecular formula but a different structural arrangement.

Based on the molecular structure, isomers of organic molecules are classified as constitutional isomers or stereoisomers.

Constitutional isomers differ in the connectivity of their constituent atoms. For example, 1-methoxypropane and diethyl ether are constitutional isomers, as they have the same molecular formula, C₄H₁₀O, but their atoms are connected in a different order.

Molecules in the other class of isomers, referred to as stereoisomers, have the same connectivity but differ in the spatial arrangement of their constituent atoms.

For example, cis-2-butene and trans-2-butene are stereoisomers, as they have atoms connected in the same sequence but are in different points in space. While in the cis isomer, the methyl groups are on the same side of the molecule, in the trans isomer, the methyl groups are on the opposite sides of the molecule.

A chiral molecule and its mirror image are stereoisomers of each other. For example, the chiral molecule 2-butanol and its mirror image are stereoisomers, as these two configurations are non-superposable and accordingly exhibit different spatial arra