One of two or more compounds with the same molecular formula but different arrangements of atoms. Structural isomers have different connectivity; stereoisomers (geometric and optical isomers) have the same connectivity but different spatial arrangements. Isomers can have very different properties.
Properties & Characteristics
Isomer refers to one of two or more compounds with the same molecular formula but different structural arrangements (structural isomers) or spatial arrangements (stereoisomers). Structural isomers differ in connectivity (chain isomers, position isomers, functional group isomers). Stereoisomers have the same connectivity but differ in 3D arrangement (geometric/cis-trans isomers, optical/enantiomers, conformational isomers). The number of possible isomers increases rapidly with molecular size.
Uses & Applications
Isomerism is critically important in drug development (enantiomers may differ in activity and toxicity), in petroleum chemistry (branched alkane isomers have higher octane ratings), in biochemistry (enzyme substrate specificity often distinguishes isomers), and in materials science (different polymer tacticity isomers have different properties — isotactic vs. atactic polypropylene).
Safety Information
Isomers can have dramatically different properties and hazards. Diethyl ether (a solvent) and 1,3-dioxolane are isomers with different boiling points, flammabilities, and toxicities. Pharmaceutical isomer control (enantiomeric purity) is a strict regulatory requirement to prevent administering potentially harmful non-active isomers.
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
One of two or more compounds with the same molecular formula but different arrangements of atoms. Structural isomers have different connectivity; stereoisomers (geometric and optical isomers) have the same connectivity but different spatial arrangements. Isomers can have very different properties.
Isomerism is critically important in drug development (enantiomers may differ in activity and toxicity), in petroleum chemistry (branched alkane isomers have higher octane ratings), in biochemistry (enzyme substrate specificity often distinguishes isomers), and in materials science (different polyme…
Isomers can have dramatically different properties and hazards. Diethyl ether (a solvent) and 1,3-dioxolane are isomers with different boiling points, flammabilities, and toxicities. Pharmaceutical isomer control (enantiomeric purity) is a strict regulatory requirement to prevent administering poten…
Editorial standards: Chemical data is sourced from peer-reviewed literature,
CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA,
and IAEA. For educational purposes only — always consult official SDS documentation and qualified
professionals before handling chemicals.
