Term: cis-trans isomers
https://doi.org/10.1351/goldbook.C01093

Definition:
Stereoisomeric olefins or cycloalkanes (or hetero-analogues) which differ in the positions of atoms (or groups) relative to a reference plane: in the cis-isomer the atoms are on the same side, in the trans-isomer they are on opposite sides. C01093.png

Related Terms:
1) stereoisomeric (http://doi.org/10.1351/goldbook.S05983).
2) olefins (http://doi.org/10.1351/goldbook.O04281).
3) cycloalkanes (http://doi.org/10.1351/goldbook.C01497).
4) isomer (http://doi.org/10.1351/goldbook.I03289).
5) trans (http://doi.org/10.1351/goldbook.C01092).

Image: molecular structures showing cis/trans isomerism (https://goldbook.iupac.org/img/inline/C01093.png) 

Source: PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2204 (https://doi.org/10.1351/pac199668122193)

Citation: '<i>cis</i>-<i>trans</i> isomers' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.C01093

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