izomery

Izomery, or isomers, are molecules that share the same molecular formula but differ in the arrangement of atoms. The term izomery is commonly used in Polish, while in English the broader concept is isomerism and the individual forms are isomers.

There are two main classes: structural (constitutional) isomers and stereoisomers. Structural isomers differ in how atoms are connected, leading to different skeletons or functional groups. Stereoisomers have the same connectivity but differ in spatial arrangement. Stereoisomerism includes enantiomers, which are non-superimposable mirror images, and diastereomers, which are not mirror images. A related idea is conformational isomerism, arising from rotation around single bonds, such as different chair conformations of cyclohexane.

Common examples illustrate the concept. C4H10 has two structural isomers: n-butane and isobutane (methylpropane). Lactic acid is a chiral molecule with two enantiomers, D- and L-lactic acid, while tartaric acid has a meso form in addition to its enantiomers. Enantiomers typically have identical physical properties in achiral environments but rotate plane-polarized light in opposite directions and may interact differently with biological systems. Diastereomers often show different boiling points and solubilities.

Izomery are central to chemistry, biology, and pharmacology because different isomers can exhibit markedly different reactivity, smells, flavors, or therapeutic effects despite identical formulas. The study of isomerism underpins stereochemistry, structural elucidation, and the design of compounds with desired properties.