Cyclopentene

• Formula: C₅H₈
• Molecular weight: 68.1170
• IUPAC Standard InChI: InChI=1S/C5H8/c1-2-4-5-3-1/h1-2H,3-5H2 Copy

  
• IUPAC Standard InChIKey: LPIQUOYDBNQMRZ-UHFFFAOYSA-N Copy
• CAS Registry Number: 142-29-0
• Chemical structure:
  This structure is also available as a 2d Mol file or as a computed 3d SD file
  The 3d structure may be viewed using Java or Javascript.
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• Information on this page:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • References
  • Notes
• Other data available:
  • Henry's Law data
  • Gas Chromatography
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Gas Phase Kinetics Database
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Gas phase thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
GT - Glushko Thermocenter, Russian Academy of Sciences, Moscow

Constant pressure heat capacity of gas

Condensed phase thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Constant pressure heat capacity of liquid

Phase change data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
AC - William E. Acree, Jr., James S. Chickos
CAL - James S. Chickos, William E. Acree, Jr., Joel F. Liebman, Students of Chem 202 (Introduction to the Literature of Chemistry), University of Missouri -- St. Louis
DH - Eugene S. Domalski and Elizabeth D. Hearing

Enthalpy of vaporization

Enthalpy of fusion

Entropy of fusion

Enthalpy of phase transition

Entropy of phase transition

Reaction thermochemistry data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

 +  =

By formula: H₂ + C₅H₈ = C₅H₁₀

 +  =

By formula: C₅H₈ + C₂HF₃O₂ = C₇H₉F₃O₂

 +  =

By formula: C₅H₈ + Br₂ = C₅H₈Br₂

 +  = 2 + 

By formula: C₅H₁₀ + I₂ = 2HI + C₅H₈

2 +  =  + 

By formula: 2HI + C₅H₆ = C₅H₈ + I₂

Gas phase ion energetics data

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to C₅H₈⁺ (ion structure unspecified)

Ionization energy determinations

Appearance energy determinations

IR Spectrum

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Gas Phase Spectrum

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Notice: Concentration information is not available for this spectrum and, therefore, molar absorptivity values cannot be derived.

Additional Data

Mass spectrum (electron ionization)

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

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Additional Data

UV/Visible spectrum

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Victor Talrose, Eugeny B. Stern, Antonina A. Goncharova, Natalia A. Messineva, Natalia V. Trusova, Margarita V. Efimkina

Spectrum

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Additional Data

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Allinger, Dodziuk, et al., 1982
Allinger, N.L.; Dodziuk, H.; Rogers, D.W.; Naik, S.N., Heats of hydrogenation and formation of some 5-membered ring compounds by molecular mechanics calculations and direct measurements, Tetrahedron, 1982, 38, 1593-1597. [all data]

Furuyama, Golden, et al., 1970
Furuyama, S.; Golden, D.M.; Benson, S.W., Thermochemistry of cyclopentene and cyclopentadiene from studies of gas-phase equilibria, J. Chem. Thermodyn., 1970, 2, 161-169. [all data]

Labbauf and Rossini, 1961
Labbauf, A.; Rossini, F.D., Heats of combustion, formation, and hydrogenation of 14 selected cyclomonoolefin hydrocarbons, J. Phys. Chem., 1961, 65, 476-480. [all data]

Epstein, Pitzer, et al., 1949
Epstein, M.B.; Pitzer, K.S.; Rossini, F.D., Heats, equilibrium constants, and free energies of formation of cyclopentene and cyclohexene, J. Res. NBS, 1949, 42, 379-382. [all data]

Beckett C.W., 1948
Beckett C.W., The thermodynamic properties and molecular structure of cyclopentene and cyclohexene, J. Am. Chem. Soc., 1948, 70, 4227-4230. [all data]

Dorofeeva O.V., 1986
Dorofeeva O.V., Thermodynamic properties of twenty-one monocyclic hydrocarbons, J. Phys. Chem. Ref. Data, 1986, 15, 437-464. [all data]

Epstein M.B., 1949
Epstein M.B., Heats, equilibrium constants, and free energies of formation of cyclopentene and cyclohexene, J. Res. Nat. Bur. Stand., 1949, 42, 379-382. [all data]

Furuyama S., 1970
Furuyama S., Thermochemistry of cyclopentene and cyclopentadiene from studies of gas-phase equilibria, J. Chem. Thermodyn., 1970, 2, 161-169. [all data]

Draeger J.A., 1983
Draeger J.A., Chemical thermodynamic properties of molecules that undergo inversion. I. Aniline, methylamine, cyclopropylamine, and cyclopentene, J. Chem. Thermodyn., 1983, 15, 367-376. [all data]

Lenz T.G., 1989
Lenz T.G., Force-field calculations giving accurate conformation, Hf(T), S(T), and Cp(T) for unsaturated acyclic and cyclic hydrocarbons, J. Phys. Chem., 1989, 93, 1588-1592. [all data]

Lenz T.G., 1990
Lenz T.G., Force field calculation of equilibrium thermodynamic properties: Diels-Alder reaction of 1,3-butadiene and ethylene and Diels-Alder dimerization of 1,3-butadiene, J. Comput. Chem., 1990, 11, 351-360. [all data]

Huffman, Eaton, et al., 1948
Huffman, H.M.; Eaton, M.; Oliver, G.D., The heat capacities, heats of transition, heats of fusion and entropies of cyclopentene and cyclohexene, J. Am. Chem. Soc., 1948, 70, 2911-2914. [all data]

Huffman, Eaton, et al., 1948, 2
Huffman, H.M.; Eaton, M.; Oliver, G.D., The heat capacities, heats of transition, heats of fusion and entropies of cyclopentene and cyclohexene, J. Am. Chem. Soc., 1948, 70, 2911. [all data]

Tsonopoulos and Ambrose, 1996
Tsonopoulos, C.; Ambrose, D., Vapor-Liquid Critical Properties of Elements and Compounds. 6. Unsaturated Aliphatic Hydrocarbons, J. Chem. Eng. Data, 1996, 41, 645-656. [all data]

Teja and Anselme, 1990
Teja, A.S.; Anselme, M.J., The critical properties of thermally stable and unstable fluids. II. 1986 results, AIChE Symp. Ser., 1990, 86, 279, 122-7. [all data]

Teja and Rosenthal, 1990
Teja, A.S.; Rosenthal, D.J., The Critical Pressures and Temperatures of Twelve Substances Using A Low Residence Time Flow Apparatus, AIChE Symp. Ser., 1990, 86, 279, 133-7. [all data]

Ambrose and Grant, 1957
Ambrose, D.; Grant, D.G., The Critical Temperatures of Some Hydrocarbons and Pyridine Bases, Trans. Faraday Soc., 1957, 53, 771. [all data]

Lister, 1941
Lister, M.W., Heats of organic reactions. X. Heats of bromination of cyclic olefins, J. Am. Chem. Soc., 1941, 63, 143-149. [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Forziati, Camin, et al., 1950
Forziati, A.F.; Camin, D.L.; Rossini, F.D., Density, refractive index, boiling point, and vapor pressure of eight monoolefin (1-alkene), six pentadiene, and two cyclomonoolefin hydrocarbons, J. RES. NATL. BUR. STAN., 1950, 45, 5, 406, https://doi.org/10.6028/jres.045.044 . [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [all data]

Roth and Lennartz, 1980
Roth, W.R.; Lennartz, H.W., Heats of hydrogenation. I. Determination of heats of hydrogenation with an isothermal titration calorimeter, Chem. Ber., 1980, 113, 1806-1817. [all data]

Turner, Jarrett, et al., 1973
Turner, R.B.; Jarrett, A.D.; Goebel, P.; Mallon, B.J., Heats of hydrogenation. 9. Cyclic acetylenes and some miscellaneous olefins, J. Am. Chem. Soc., 1973, 95, 790-792. [all data]

Rogers and McLafferty, 1971
Rogers, D.W.; McLafferty, F.J., A new hydrogen calorimeter. Heats of hydrogenation of allyl and vinyl unsaturation adjacent to a ring, Tetrahedron, 1971, 27, 3765-3775. [all data]

Dolliver, Gresham, et al., 1937
Dolliver, M.a.; Gresham, T.L.; Kistiakowsky, G.B.; Vaughan, W.E., Heats of organic reactions. V. Heats of hydrogenation of various hydrocarbons, J. Am. Chem. Soc., 1937, 59, 831-841. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Wiberg, Wasserman, et al., 1985
Wiberg, K.B.; Wasserman, D.J.; Martin, E.J.; Murcko, M.A., Enthalpies of hydration of alkenes. 3. Cycloalkenes, J. Am. Chem. Soc., 1985, 107, 6019-6022. [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Harris, McKinnon, et al., 1979
Harris, D.; McKinnon, S.; Boyd, R.K., The origins of the base peak in the electron impact spectrum of limonene, Org. Mass Spectrom., 1979, 14, 265. [all data]

Bieri, Burger, et al., 1977
Bieri, G.; Burger, F.; Heilbronner, E.; Maier, J.P., Valence ionization enrgies of hydrocarbons, Helv. Chim. Acta, 1977, 60, 2213. [all data]

Lossing and Traeger, 1975
Lossing, F.P.; Traeger, J.C., Stabilization in cyclopentadienyl, cyclopentenyl, and cyclopentyl cations, J. Am. Chem. Soc., 1975, 97, 1579. [all data]

Rang, Paldoia, et al., 1974
Rang, S.; Paldoia, P.; Talvari, A., Ionization potentials of unsaturated hydrocarbons. 2. Mono-substituted cyclopentenes and cyclohexenes, Eesti. NSV Tead. Akad. Toim., 1974, 354. [all data]

Holmes, 1974
Holmes, J.L., The mass spectra of isomeric hydrocarbons - II: The C₅H₈ isomers, spiropentane, cyclopentene, 1,3-pentadiene and isoprene; the mechanisms and energetics of their fragmentations, Org. Mass Spectrom., 1974, 8, 247. [all data]

Praet and Delwiche, 1970
Praet, M.-T.; Delwiche, J., Ionization energies of some cyclic molecules, Chem. Phys. Lett., 1970, 5, 546. [all data]

Demeo and El-Sayed, 1970
Demeo, D.A.; El-Sayed, M.A., Ionization potential and structure of olefins, J. Chem. Phys., 1970, 52, 2622. [all data]

Bischof and Heilbronner, 1970
Bischof, P.; Heilbronner, E., Photoelektron-Spektren von Cycloalkenen und Cycloalkadienen, Helv. Chim. Acta, 1970, 53, 1677. [all data]

Dewar and Worley, 1969
Dewar, M.J.S.; Worley, S.D., Photoelectron spectra of molecules. I. Ionization potentials of some organic molecules and their interpretation, J. Chem. Phys., 1969, 50, 654. [all data]

Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J., Ionization potentials of some molecules, J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [all data]

Wiberg, Ellison, et al., 1976
Wiberg, K.B.; Ellison, G.B.; Wendoloski, J.J.; Brundle, C.R.; Kuebler, N.A., Electronic states of organic molecules. 3. Photoelectron spectra of cycloalkenes and methylenecycloalkanes, J. Am. Chem. Soc., 1976, 98, 7179. [all data]

Heilbronner, Hoshi, et al., 1976
Heilbronner, E.; Hoshi, T.; von Rosenberg, J.L.; Hafner, K., Alkyl-induced, natural hypsochromic shifts of the ²A←²X and ²B←²X transitions of azulene and naphthalene radical cations, Nouv. J. Chim., 1976, 1, 105. [all data]

Bertoti, Cradock, et al., 1976
Bertoti, I.; Cradock, S.; Ebsworth, E.A.V.; Whiteford, R.A., Photoelectron spectra and transannular interactions in 1-silacyclopent-3-enes, J. Chem. Soc. Dalton Trans., 1976, 937. [all data]

Hentrich, Gunkel, et al., 1974
Hentrich, G.; Gunkel, E.; Klessinger, M., Photoelektronenspektren organischer verbindungen. 4. Photoelektronenspektren ungesattigter carbonylverbindungen, J. Mol. Struct., 1974, 21, 231. [all data]

Clary, Lewis, et al., 1974
Clary, D.C.; Lewis, A.A.; Morland, D.; Murrell, J.N.; Heilbronner, E., Ionization potentials of cycloalkenes, J. Chem. Soc. Faraday Trans. 2, 1974, 70, 1889. [all data]

Batich, Heilbronner, et al., 1974
Batich, C.; Heilbronner, E.; Rommel, E.; Semmelhack, M.F.; Foos, J.S., Equivalence of the energy gaps {DELTA}I(1,2) and {DELTA}E(1,2) between corresponding bands in the photoelectron (I) and electronic absorption (E) spectra of spiro[4.4]nonatetraene. An amusing consequence of spiroconjugation, J. Am. Chem. Soc., 1974, 96, 7662. [all data]

Lossing and Traeger, 1975, 2
Lossing, F.P.; Traeger, J.C., Free radicals by mass spectrometry XLVI. Heats of formation of C₅H₇ and C₅H₉ radicals and cations., J. Am. Chem. Soc., 1975, 19, 9. [all data]

Pignataro, Cassuto, et al., 1967
Pignataro, S.; Cassuto, A.; Lossing, F.P., Free radicals by mass spectrometry. XXXVI. Ionization potentials of conjugated and nonconjugated radicals, J. Am. Chem. Soc., 1967, 89, 3693. [all data]

Pickett, Muntz, et al., 1951
Pickett, L.W.; Muntz, M.; McPherson, E.M., Vacuum ultraviolet absorption spectra of cyclic compounds. I. Cyclohexane, cyclohexene, cyclopentane, Cyclopentene and benzene, J. Am. Chem. Soc., 1951, 73, 4862-4865. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, References

• Symbols used in this document:
  

  AE	Appearance energy
  Cp,gas	Constant pressure heat capacity of gas
  Cp,liquid	Constant pressure heat capacity of liquid
  IE (evaluated)	Recommended ionization energy
  Pc	Critical pressure
  S°gas	Entropy of gas at standard conditions
  S°liquid	Entropy of liquid at standard conditions
  Tboil	Boiling point
  Tc	Critical temperature
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  Vc	Critical volume
  ΔHtrs	Enthalpy of phase transition
  ΔStrs	Entropy of phase transition
  ΔcH°liquid	Enthalpy of combustion of liquid at standard conditions
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔfH°liquid	Enthalpy of formation of liquid at standard conditions
  ΔfusH	Enthalpy of fusion
  ΔfusS	Entropy of fusion
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔvapH	Enthalpy of vaporization
  ΔvapH°	Enthalpy of vaporization at standard conditions
  ρc	Critical density

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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