AllChemicals — The Online Chemical Glossary | https://allchemicals.info/chemical/271-cis
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Quick Reference
Also Known As
Cis isomer, Z-isomer (CIP rules), syn (in some naming systems)
What is Cis?
Cis is a Latin prefix meaning "on the same side", used in chemistry to describe geometric isomers in which identical or similar substituents are on the same side of a double bond or ring. In cis-2-butene, both methyl groups are on the same side of the C=C double bond, contrasting with the trans isomer where they are on opposite sides.
Properties & Characteristics
Cis refers to a geometric isomer in which identical or similar substituents are on the same side of a double bond, ring, or other restricted-rotation system. In alkenes, cis isomers (also called Z-isomers by the Cahn-Ingold-Prelog priority rules when priorities are on the same side) generally have higher dipole moments, lower melting points, but often higher boiling points than their trans counterparts. The prefix derives from Latin: "on this side."
Uses & Applications
The cis/trans distinction is critical in biochemistry: cis-fatty acids (unsaturated, kinked chains) are liquid at room temperature, while trans-fatty acids behave like saturated fats and are linked to cardiovascular disease. Cis-platinum (cisplatin) is an anticancer drug; its trans isomer is inactive.
Safety Information
Some cis isomers are significantly more toxic or pharmacologically active than their trans counterparts. Always verify the specific isomer when working with drugs, natural products, or environmental contaminants. Trans-fatty acid consumption is regulated in many countries.
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
SynonymsCis isomer, Z-isomer (CIP rules), syn (in some naming systems)
Frequently Asked Questions
Cis is a Latin prefix meaning "on the same side", used in chemistry to describe geometric isomers in which identical or similar substituents are on the same side of a double bond or ring. In cis-2-butene, both methyl groups are on the same side of the C=C double bond, contrasting with the trans isomer where they are on opposite sides.
The cis/trans distinction is critical in biochemistry: cis-fatty acids (unsaturated, kinked chains) are liquid at room temperature, while trans-fatty acids behave like saturated fats and are linked to cardiovascular disease. Cis-platinum (cisplatin) is an anticancer drug; its trans isomer is inactiv…
Some cis isomers are significantly more toxic or pharmacologically active than their trans counterparts. Always verify the specific isomer when working with drugs, natural products, or environmental contaminants. Trans-fatty acid consumption is regulated in many countries.
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.
