Cyclohexene

Athanor · official

C₆H₁₀ · 82.14 g/mol

Rings

Open in Athanor

Drawn from its SMILES with RDKit

DangerHighly Flammable liquid and vapor · Harmful if swallowed · May be fatal if swallowed and enters airways · Toxic in contact with skin · Toxic to aquatic life with long lasting effects

Names and identifiers

IUPAC name: cyclohexene
Synonyms: Tetrahydrobenzene, Cyclohex-1-ene, Benzene tetrahydride
+ 34 more
1,2,3,4-Tetrahydrobenzene, Benzenetetrahydride, Hexanaphthylene, Cykloheksen, Benzene, tetrahydro-, 3,4,5,6-Tetrahydrobenzene, 12L0P8F7GN, DTXSID9038717, NSC-24835, CHEBI:36404, RefChem:129655, DTXCID7018717, 203-807-8, 1-Cyclohexene, Zyklohexen, MFCD00001539, NSC 24835, Cykloheksen [Polish], cyclohexen, HSDB 1624, EINECS 203-807-8, UN2256, BRN 0906737, cylcohexene, UNII-12L0P8F7GN, cyclo hexene, cyclo-hexene, cyclohexane N, AI3-03146, CCRIS 8739, 2-cyclohexen, UN 2256, A1ADK, CYCLOHEXENE [MI]
Molecular formula: C₆H₁₀
Empirical formula: C₃H₅
Molecular weight: 82.14 g/mol
Exact mass: 82.07825
CAS number: 110-83-8
PubChem CID: 8079
Canonical SMILES: C1CCC=CC1
Isomeric SMILES: C1CCC=CC1
InChI: InChI=1S/C6H10/c1-2-4-6-5-3-1/h1-2H,3-6H2
InChIKey: HGCIXCUEYOPUTN-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Colorless liquid[5]
5 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Cyclohexene appears as a colorless liquid. Insoluble in water and less dense than water. Flash point 20 °F. Vapors heavier than air. Inhalation of high concentrations may have a narcotic effect. Used to make other chemicals. [1] CAMEO Chemicals
– COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR. [2] ILO-WHO International Chemical Safety Cards (ICSCs)
– Colorless liquid with a sweet odor. [3] Occupational Safety and Health Administration (OSHA)
– Colorless liquid with a sweet odor. [4] The National Institute for Occupational Safety and Health (NIOSH)
–shown Colorless liquid [5] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 321
Odor: Sweet odor[5]
Melting point: -103.7 °C[6]
5 values
5 of 5 sources agree on it (most common value).
Value As written Source
−103 °C -154 °F (NIOSH, 2024) [1] CAMEO Chemicals
−104 °C -104 °C [2] ILO-WHO International Chemical Safety Cards (ICSCs)
−103 °C -154 °F [3] Occupational Safety and Health Administration (OSHA)
−103.7 °Cshown -103.7 °C [6] PAC Chemical Database, U.S. Department of Energy
−103 °C -154 °F [4] The National Institute for Occupational Safety and Health (NIOSH)
Boiling point: 83 °C (181 °F) at 760 mmHg (NIOSH, 2024)[1]
5 values
5 of 5 sources agree on it (most common value).
Value As written Source
83 °Cshown 181 °F at 760 mmHg (NIOSH, 2024) [1] CAMEO Chemicals
83 °C 83 °C [2] ILO-WHO International Chemical Safety Cards (ICSCs)
83 °C 181 °F [3] Occupational Safety and Health Administration (OSHA)
83 °C 83 °C @760 [mm Hg] [6] PAC Chemical Database, U.S. Department of Energy
83 °C 181 °F [4] The National Institute for Occupational Safety and Health (NIOSH)
Density: 0.8102 @25 °C[6]
5 values
5 of 5 sources agree on it (most common value).
Value As written Source
– 0.81 (NIOSH, 2024) - Less dense than water [1] CAMEO Chemicals
– Relative density (water = 1): 0.81 [2] ILO-WHO International Chemical Safety Cards (ICSCs)
– 0.81 [3] Occupational Safety and Health Administration (OSHA)
–shown 0.8102 @25 °C [6] PAC Chemical Database, U.S. Department of Energy
– 0.81 [4] The National Institute for Occupational Safety and Health (NIOSH)
Solubility in water: Solubility in water: none[2]
4 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– Insoluble (NIOSH, 2024) [1] CAMEO Chemicals
– In water, 213 mg/L at 25 °C [5] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan., Handbook of Aqueous Solubility Data: An Extensive Compilation of Aqueous Solubility Data for Organic Compounds Extracted from the AQUASOL dATAbASE. CRC Press LLC, Boca Raton, FL. 2003., p. 283
–shown Solubility in water: none [2] ILO-WHO International Chemical Safety Cards (ICSCs)
– Insoluble [4] The National Institute for Occupational Safety and Health (NIOSH)
log P: 2.86[2]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
– log Kow = 2.86 [5] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 23
–shown 2.86 [2] ILO-WHO International Chemical Safety Cards (ICSCs)
Vapor pressure: Vapor pressure, kPa at 20 °C: 8.9[2]
2 values
Sources disagree; from ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative.
Value As written Source
67 mmHgshown Vapor pressure, kPa at 20 °C: 8.9 [2] ILO-WHO International Chemical Safety Cards (ICSCs)
89 mmHg 89 [mm Hg] @25 °C [6] PAC Chemical Database, U.S. Department of Energy
3 more values were reported but failed the checks (unreadable or out of range), so they are not shown.
Flash point: -12 °C (11 °F, NIOSH 2024)[1]
5 values
3 of 4 sources agree on it (most common value).
Value As written Source
−12 °Cshown 11 °F (NIOSH, 2024) [1] CAMEO Chemicals
< −7 °C <20 °F (<-7 °C) (Closed cup) [5] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-34
−6 °C -6 °C c.c. [2] ILO-WHO International Chemical Safety Cards (ICSCs)
−12 °C 11 °F [3] Occupational Safety and Health Administration (OSHA)
−12 °C 11 °F [4] The National Institute for Occupational Safety and Health (NIOSH)
Autoignition temperature: 244 °C[2]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
244 °C 471 °F (244 °C) [5] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-34
244 °Cshown 244 °C [2] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	Cyclohexene appears as a colorless liquid. Insoluble in water and less dense than water. Flash point 20 °F. Vapors heavier than air. Inhalation of high concentrations may have a narcotic effect. Used to make other chemicals.	[1] CAMEO Chemicals
–	COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Colorless liquid with a sweet odor.	[3] Occupational Safety and Health Administration (OSHA)
–	Colorless liquid with a sweet odor.	[4] The National Institute for Occupational Safety and Health (NIOSH)
–shown	Colorless liquid	[5] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 14th Edition. John Wiley & Sons, Inc. New York, NY 2001., p. 321

Value	As written	Source
−103 °C	-154 °F (NIOSH, 2024)	[1] CAMEO Chemicals
−104 °C	-104 °C	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
−103 °C	-154 °F	[3] Occupational Safety and Health Administration (OSHA)
−103.7 °Cshown	-103.7 °C	[6] PAC Chemical Database, U.S. Department of Energy
−103 °C	-154 °F	[4] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
83 °Cshown	181 °F at 760 mmHg (NIOSH, 2024)	[1] CAMEO Chemicals
83 °C	83 °C	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
83 °C	181 °F	[3] Occupational Safety and Health Administration (OSHA)
83 °C	83 °C @760 [mm Hg]	[6] PAC Chemical Database, U.S. Department of Energy
83 °C	181 °F	[4] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	0.81 (NIOSH, 2024) - Less dense than water	[1] CAMEO Chemicals
–	Relative density (water = 1): 0.81	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
–	0.81	[3] Occupational Safety and Health Administration (OSHA)
–shown	0.8102 @25 °C	[6] PAC Chemical Database, U.S. Department of Energy
–	0.81	[4] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	Insoluble (NIOSH, 2024)	[1] CAMEO Chemicals
–	In water, 213 mg/L at 25 °C	[5] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan., Handbook of Aqueous Solubility Data: An Extensive Compilation of Aqueous Solubility Data for Organic Compounds Extracted from the AQUASOL dATAbASE. CRC Press LLC, Boca Raton, FL. 2003., p. 283
–shown	Solubility in water: none	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Insoluble	[4] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	log Kow = 2.86	[5] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 23
–shown	2.86	[2] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
67 mmHgshown	Vapor pressure, kPa at 20 °C: 8.9	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
89 mmHg	89 [mm Hg] @25 °C	[6] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
−12 °Cshown	11 °F (NIOSH, 2024)	[1] CAMEO Chemicals
< −7 °C	<20 °F (<-7 °C) (Closed cup)	[5] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-34
−6 °C	-6 °C c.c.	[2] ILO-WHO International Chemical Safety Cards (ICSCs)
−12 °C	11 °F	[3] Occupational Safety and Health Administration (OSHA)
−12 °C	11 °F	[4] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
244 °C	471 °F (244 °C)	[5] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-34
244 °Cshown	244 °C	[2] ILO-WHO International Chemical Safety Cards (ICSCs)

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 6
Rings: 1
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0.67
H-bond donors: 0
H-bond acceptors: 0
Rotatable bonds: 0
TPSA (Å²): 0
Formal charge: 0
XLogP3: 2.9 PubChem
Complexity: 45 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C2 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C87.73%
H12.27%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 2.12 Crippen (Wildman and Crippen 1999)
log S (water solubility): -1.68 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 2.42 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 82.15
log P ≤ 5 (Crippen): 2.12
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 0

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Most widely reported: 104 company reports to ECHA. Source [7].

Flammable
Acute toxicity
Harmful or irritant
Health hazard
Environmental hazard

NFPA 704[5]

H225Highly Flammable liquid and vapor
H302Harmful if swallowed
H304May be fatal if swallowed and enters airways (95.2% of reports)
H311Toxic in contact with skin (39.4% of reports)
H411Toxic to aquatic life with long lasting effects (57.7% of reports)

Precautionary statements: P210, P233, P240, P241, P242, P243, P262, P264, P270, P273, P280, P301+P316, P301+P317, P302+P352, P303+P361+P353, P316, P321, P330, P331, P361+P364, P370+P378, P391, P403+P235, P405, P501

Exposure limits

PEL-TWA (8-Hour Time Weighted Average): 300 ppm (1015 mg/m³)[3]
PEL: TWA 300 ppm (1015 mg/m3)[4]
REL-TWA (Time Weighted Average): 300 ppm[3]
TLV: 20 ppm as TWA[2]
TLV-TWA (Time Weighted Average): 20 ppm (67 mg/m3) [2020][3]
IDLH: 2000 ppm (NIOSH, 2024)[1]

First aid

Excerpt from NIOSH Pocket Guide for Cyclohexene: Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: SOAP WASH promptly - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water.[1]
General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[8]
(General first aid procedures) Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: Soap wash promptly - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water.[4]
Fresh air, rest.[2]

Storage

Fireproof. Separated from strong oxidants. Cool. Well closed. Store only if stabilized.[2]
A harmful contamination of the air will be reached rather slowly on evaporation of this substance at 20 °C.[5]

Incompatibilities

Strong oxidizers [Note: Forms explosive peroxides with oxygen upon storage.][5]

Safety data sheets on the supplier’s page: Mcule, 001Chemical, Enamine.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[3]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
[4]The National Institute for Occupational Safety and Health (NIOSH) · Public domain (US CDC) · via PubChem · retrieved 2026-10-14
[5]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[6]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[7]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[8]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
[9]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[10]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[11]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[12]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[13]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.