Isomeria

Isomeria is a phenomenon in chemistry where compounds have the same molecular formula but different structural formulas. This means the atoms are connected in a different order, leading to distinct physical and chemical properties. Isomers are compounds that exhibit this relationship.

There are two main categories of isomerism: structural isomerism and stereoisomerism. Structural isomerism, also known as constitutional isomerism, arises from differences in the connectivity of atoms within the molecule. For example, butane and isobutane (or 2-methylpropane) are structural isomers, both having the formula C4H10.

Stereoisomerism, on the other hand, occurs when isomers have the same connectivity but differ in the spatial arrangement of their atoms. This can be further divided into enantiomers and diastereomers. Enantiomers are stereoisomers that are non-superimposable mirror images of each other, much like left and right hands. Diastereomers are stereoisomers that are not mirror images of each other. Geometric isomerism (cis-trans isomerism) is a type of diastereomerism often found in compounds with restricted rotation, such as double bonds. The presence of isomers can significantly impact a molecule's biological activity and reactivity.