The phenomenon where two or more compounds share the same molecular formula but differ in structural arrangement or spatial orientation of atoms. Types include constitutional (structural), geometric (cis/trans), and optical (enantiomers/diastereomers) isomerism.
Formula & Notation
CₙH₂ₙ₋₂ (cycloalkane CₙH₂ₙ) | Multiple types of isomers possible
Types: (1) Constitutional/structural: same formula, different connectivity (chain, position, functional group isomers). (2) Stereoisomers — same connectivity, different 3D arrangement: geometric (cis/trans around double bond or ring), optical (mirror images, chiral compounds — enantiomers). Diastereomers: stereoisomers not mirror images. Chiral center: carbon bonded to four different groups. Optical rotation: d/+ dextrorotatory, l/− levorotatory. Racemic mixture: equal enantiomers, net zero rotation.
Uses & Applications
Drug design: enantiomers often have different biological activities (thalidomide S=teratogenic, R=therapeutic). Flavor and fragrance: (R)-carvone (spearmint), (S)-carvone (caraway). Amino acids: all naturally occurring are L-configuration. Sugars: D-glucose (blood sugar) vs L-glucose (not metabolized). Industrial separation of enantiomers using chiral HPLC, chiral resolution, enzyme-catalyzed routes. Geometric isomers: cis-platin (anticancer) vs trans-platin (inactive).
Safety Information
Optical isomers can have dramatically different toxicities and therapeutic effects. Thalidomide caused birth defects due to racemic mixture use — now single enantiomer drugs required. (S)-ibuprofen is the active form; (R)-ibuprofen converts slowly in vivo. Always verify stereochemistry when working with chiral compounds in pharmaceutical synthesis.
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
TermIsomerism
FormulaCₙH₂ₙ₋₂ (cycloalkane CₙH₂ₙ) | Multiple types of isomers possible
The phenomenon where two or more compounds share the same molecular formula but differ in structural arrangement or spatial orientation of atoms. Types include constitutional (structural), geometric (cis/trans), and optical (enantiomers/diastereomers) isomerism.
Drug design: enantiomers often have different biological activities (thalidomide S=teratogenic, R=therapeutic). Flavor and fragrance: (R)-carvone (spearmint), (S)-carvone (caraway). Amino acids: all naturally occurring are L-configuration. Sugars: D-glucose (blood sugar) vs L-glucose (not metabolize…
Optical isomers can have dramatically different toxicities and therapeutic effects. Thalidomide caused birth defects due to racemic mixture use — now single enantiomer drugs required. (S)-ibuprofen is the active form; (R)-ibuprofen converts slowly in vivo. Always verify stereochemistry when working …
The formula or notation for Isomerism is: CₙH₂ₙ₋₂ (cycloalkane CₙH₂ₙ) | Multiple types of isomers possible
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.
