stereoisomeriikka

Stereoisomerism is a type of isomerism in chemistry where molecules have the same molecular formula and the same constitution but differ in the spatial arrangement of their atoms. This difference in three-dimensional structure leads to distinct physical and chemical properties. Stereoisomers are not superimposable on their mirror images or on each other. There are two main types of stereoisomerism: enantiomerism and diastereomerism.

Enantiomers are stereoisomers that are non-superimposable mirror images of each other. They are often described as chiral molecules. A classic example is a pair of hands; your left hand and right hand are mirror images but cannot be perfectly superimposed. Enantiomers have identical physical properties like melting point and boiling point, but they differ in their interaction with plane-polarized light, rotating it in opposite directions. They can also have different biological activities.

Diastereomers are stereoisomers that are not mirror images of each other. This occurs in molecules with more than one chiral center or in molecules with double bonds that exhibit cis-trans isomerism. Unlike enantiomers, diastereomers generally have different physical and chemical properties. For instance, cis and trans isomers of alkenes have different boiling points and reactivity. The presence of multiple chiral centers in a molecule can lead to multiple sets of enantiomers and diastereomers. Understanding stereoisomerism is crucial in fields like organic chemistry, biochemistry, and pharmacology, as the specific spatial arrangement of atoms can significantly impact a molecule's function and behavior.