Cyclopentene
A five-membered cyclic alkene with localized double-bond reactivity.
- Formula
- C5H8
- Functional group
- Alkenes
- Molar mass
- 68.12 g/mol
- Also known as
- 1-Cyclopentene, ONM2CKV81Z
Overview
A five-membered cyclic alkene with localized double-bond reactivity.
Addition of bromine can convert its double bond into adjacent carbon–bromine bonds. Ring connectivity remains intact in this addition. A cyclic alkene must therefore be distinguished from an aromatic ring, whose characteristic electrophilic reactions usually retain the aromatic system.
Identifiers
- Formula
- C5H8
- Functional group
- Alkenes
- Molar mass
- 68.12 g/mol
- Also known as
- 1-Cyclopentene, ONM2CKV81Z
Chemical identifiers
- SMILES
- C1CC=CC1
- InChI
- InChI=1S/C5H8/c1-2-4-5-3-1/h1-2H,3-5H2
- PubChem CID
- 8882
Properties
- Melting Point
- -211 °F (USCG, 1999)
- Boiling Point
- 112 °F at 760 mmHg (USCG, 1999)
Data availability
Not published: Density, Solubility.
Related compounds
- Alkenes
A five-membered cyclic alkene with localized double-bond reactivity.
References
- PubChem Compound Summary: Cyclopentene (CID 8882)National Center for Biotechnology Information · PubChem
Identity, molecular formula, molecular weight and aliases retrieved via PUG REST on 2026-09-08.
- OpenStax Organic Chemistry: Halogenation of alkenes: addition of X2John McMurry · OpenStax · 2023
Supports the qualitative structure and reactivity context; identity and numerical measurements retain their original references.
- CAMEO Chemicals: Cyclopentene — melting pointCAMEO Chemicals
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/8882#section=Melting-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
- CAMEO Chemicals: Cyclopentene — boiling pointCAMEO Chemicals
Retrieved through PubChem PUG View on 2026-09-08. https://pubchem.ncbi.nlm.nih.gov/compound/8882#section=Boiling-Point. Source value, complete property clause or compact miscibility statement retained; absent pressure, temperature or phase conditions are not inferred. Original reference: U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.