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
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• Information on this page:
  • Gas phase thermochemistry data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Phase change data
  • Henry's Law data
  • IR Spectrum
  • Gas Chromatography
• Data at other public NIST sites:
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  • 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

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

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, Reaction thermochemistry data, Gas phase ion energetics data, 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]

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]

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]

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, Reaction thermochemistry data, Gas phase ion energetics data, Mass spectrum (electron ionization), UV/Visible spectrum, References

• Symbols used in this document:
  

  AE	Appearance energy
  Cp,gas	Constant pressure heat capacity of gas
  IE (evaluated)	Recommended ionization energy
  S°gas	Entropy of gas at standard conditions
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions

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