1,3-Cyclopentadiene

• Formula: C₅H₆
• Molecular weight: 66.1011
• IUPAC Standard InChI: InChI=1S/C5H6/c1-2-4-5-3-1/h1-4H,5H2 Copy

  
• IUPAC Standard InChIKey: ZSWFCLXCOIISFI-UHFFFAOYSA-N Copy
• CAS Registry Number: 542-92-7
• 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.
• Other names: Cyclopentadiene; Pentole; Pyropentylene; R-Pentine
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Phase change data
  • Gas phase ion energetics data
  • Gas Chromatography
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Reaction thermochemistry data
  • Ion clustering data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Gas Phase Kinetics Database
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Phase change data

Go To: Top, Gas phase ion energetics data, Gas Chromatography, References, Notes

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
DH - Eugene S. Domalski and Elizabeth D. Hearing

Enthalpy of vaporization

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (bar)
    T = temperature (K)

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Enthalpy of fusion

Entropy of fusion

Gas phase ion energetics data

Go To: Top, Phase change data, Gas Chromatography, References, Notes

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:
B - John E. Bartmess
MM - Michael M. Meot-Ner (Mautner)
LL - Sharon G. Lias and Joel F. Liebman
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 C₅H₆⁺ (ion structure unspecified)

Proton affinity at 298K

Gas basicity at 298K

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

 +  =

By formula: C₅H₅^- + H⁺ = C₅H₆

Gas Chromatography

Go To: Top, Phase change data, Gas phase ion energetics data, References, Notes

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

Kovats' RI, non-polar column, isothermal

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Kovats' RI, non-polar column, custom temperature program

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Kovats' RI, polar column, isothermal

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Kovats' RI, polar column, temperature ramp

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Normal alkane RI, non-polar column, isothermal

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Normal alkane RI, non-polar column, temperature ramp

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Normal alkane RI, non-polar column, custom temperature program

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Lee's RI, non-polar column, temperature ramp

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References

Go To: Top, Phase change data, Gas phase ion energetics data, Gas Chromatography, Notes

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

Murphy and Duggan, 1949
Murphy, M.T.; Duggan, A.C., Pyrolysis of Butadiene, J. Am. Chem. Soc., 1949, 71, 3347. [all data]

Staudinger, 1926
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Lebedev and Lityagov, 1977
Lebedev, B.V.; Lityagov, V.Ya., Thermodynamics of polypentenamer synthesis reactions crystalline polytetrahydrofuran at 0 K, Vysokomol. Soedin., Ser. B, 1977, 19, 558. [all data]

Rogers, 1972
Rogers, F.E., Thermochemistry of the Diels-Alder reactions. II. Heat of addition of several dienes to tetracyanoethylene, J. Phys. Chem., 1972, 76, 106-109. [all data]

Hull, Reid, et al., 1965
Hull, H.S.; Reid, A.F.; Turnbull, A.G., Vapour pressures of cyclopentadiene and bis(cyclopentadienyl)magnesium, Aust. J. Chem., 1965, 18, 249. [all data]

Hull, Reid, et al., 1965, 2
Hull, HS; Reid, AF; Turnbull, AG, Vapour pressures of cyclopentadiene and Bis(cyclopentadienyl)magnesium, Aust. J. Chem., 1965, 18, 2, 249-621, https://doi.org/10.1071/CH9650249 . [all data]

Barrett and Burrage, 1932
Barrett, E.G.V.; Burrage, L.J., Some Observations on the Transformation of Cyclopentadiene into its Dimeride., J. Phys. Chem., 1932, 37, 8, 1029-1035, https://doi.org/10.1021/j150350a007 . [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]

Lesteva, Ogorodnikov, et al., 1967
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Boublik, Fried, et al., 1984
Boublik, T.; Fried, V.; Hala, E., The Vapour Pressures of Pure Substances: Selected Values of the Temperature Dependence of the Vapour Pressures of Some Pure Substances in the Normal and Low Pressure Region, 2nd ed., Elsevier, New York, 1984, 972. [all data]

Lesteva, Ogoradnikov, et al., 1967
Lesteva, T.M.; Ogoradnikov, S.K.; Morozova, A., Kinetics of Dimerisation of Cyclopentadiene and Equilibrium of Liquid-Steam in System of Isoprene-Cyclopentadiene, Zh. Prikl. Khim. (Leningrad), 1967, 40, 891-894. [all data]

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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]

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]

Aue, Guidoni, et al., 2000
Aue, D.H.; Guidoni, M.; Betowski, L.D., Ab initio calculated gas-phase basicities of polynuclear aromatic hydrocarbons, Int. J. Mass Spectrom., 2000, 201, 283. [all data]

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Kiselev, V.D.; Sakhabutdinov, A.G.; Shakirov, I.M.; Zverev, V.V.; Konovalov, A.I., Bis reactants in Diels-Alder reactions. VII. Preparation and properties of polyadducts of reactions of bis(polymethylcyclopentadienes) and bis(maleimides), Zh. Org. Khim., 1992, 28, 2244. [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]

Holmes and McGillivray, 1971
Holmes, J.L.; McGillivray, D., The mass spectra of isomeric hydrocarbons-I: Norbornene and nortricyclene; The mechanisms and energetics of their fragmentations, Org. Mass Spectrom., 1971, 5, 1349. [all data]

Derrick, Asbrink, et al., 1971
Derrick, P.J.; Asbrink, L.; Edqvist, O.; Jonsson, B.-O.; Lindholm, E., Rydberg series in small molecules. XIII. Photoelectron spectroscopy and electronic structure of cyclopentadiene, Intern. J. Mass Spectrom. Ion Phys., 1971, 6, 203. [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]

Hedaya, Kent, et al., 1968
Hedaya, E.; Kent, M.E.; McNeil, D.W.; Lossing, F.P.; McAllister, T., The thermal rearrangement of phenylnitrene to cyanocyclopentadiene, Tetrahedron Lett., 1968, 30, 3415. [all data]

Dewar and Worley, 1968
Dewar, M.J.S.; Worley, S.D., Ionization potential of cis-1,3-butadiene, J. Chem. Phys., 1968, 49, 2454. [all data]

Bock and Kaim, 1980
Bock, H.; Kaim, W., Radical ions. 37. Ionization and one-electron oxidation of electron-rich silylalkyl olefins, J. Am. Chem. Soc., 1980, 102, 4429. [all data]

Cradock, Ebsworth, et al., 1975
Cradock, S.; Ebsworth, E.A.V.; Moretto, H.; Rankin, D.W.H., Photoelectron spectra and fluxional behaviour in some σ-cyclopentadienes, J. Chem. Soc. Dalton Trans., 1975, 390. [all data]

Cradock, Findlay, et al., 1974
Cradock, S.; Findlay, R.H.; Palmer, M.H., Bonding in methyl- and silyl-cyclopentadiene compounds: a study by photoelectron spectroscopy ab initio molecular-orbital calculations, J. Chem. Soc. Dalton Trans., 1974, 1650. [all data]

Occolowitz and White, 1968
Occolowitz, J.L.; White, G.L., Energetic considerations in the assignment of some fragment ion structures, Australian J. Chem., 1968, 21, 997. [all data]

Harrison, Haynes, et al., 1965
Harrison, A.G.; Haynes, P.; McLean, S.; Meyer, F., The mass spectra of methyl-substituted cyclopentadienes, J. Am. Chem. Soc., 1965, 87, 5099. [all data]

Dorman, 1965
Dorman, F.H., Second differential ionization-efficiency curves for fragment ions by electron impact, J. Chem. Phys., 1965, 43, 3507. [all data]

Harrison, Honnen, et al., 1960
Harrison, A.G.; Honnen, L.R.; Dauben, H.J., Jr.; Lossing, F.P., Free radicals by mass spectrometry. XX. Ionization potentials of cyclopentadienyl and cycloheptatrienyl radicals, J. Am. Chem. Soc., 1960, 82, 5593. [all data]

Bartmess, Scott, et al., 1979
Bartmess, J.E.; Scott, J.A.; McIver, R.T., Jr., The gas phase acidity scale from methanol to phenol, J. Am. Chem. Soc., 1979, 101, 6047. [all data]

Cumming and Kebarle, 1978
Cumming, J.B.; Kebarle, P., Summary of gas phase measurements involving acids AH. Entropy changes in proton transfer reactions involving negative ions. Bond dissociation energies D(A-H) and electron affinities EA(A), Can. J. Chem., 1978, 56, 1. [all data]

Engelking and Lineberger, 1977
Engelking, P.C.; Lineberger, W.C., Laser photoelectron spectrometry of C₅H₅-: A determination of the electron affinity and Jahn-Teller coupling in cyclopentadienyl, J. Chem. Phys., 1977, 67, 1412. [all data]

Diez, Guillen, et al., 1990
Diez, M.A.; Guillen, M.D.; Blanco, C.G.; Bermejo, J., Chromatographic study of methylcyclopentadiene dimers and iso-dimers and determination of their boiling points, J. Chromatogr., 1990, 508, 363-374, https://doi.org/10.1016/S0021-9673(00)91279-2 . [all data]

Safina, Poznyak, et al., 1989
Safina, L.R.; Poznyak, T.I.; Lisitsyn, D.M.; Kiseleva, E.V.; Kovalev, G.I., Selective gas-chromatographic determination of trace unsaturated and aromatic-hydrocarbons in complex-mixtures, J. Appl. Chem. USSR (Engl. Transl.), 1989, 44, 5, 749-754. [all data]

Papazova, Milina, et al., 1988
Papazova, D.; Milina, R.; Dimov, N., Comparative evaluation of retention of hydrocarbons present in the C₅-petroleum fraction of methylsilicone and squalane phases, Chromatographia, 1988, 25, 3, 177-180, https://doi.org/10.1007/BF02316441 . [all data]

Bermejo, Blanco, et al., 1987
Bermejo, J.; Blanco, C.G.; Diez, M.A.; Guillén, M.D., Kováts retention indices of selected mono and polycyclic olefins, J. Hi. Res. Chromatogr. Chromatogr. Comm., 1987, 10, 8, 461-463, https://doi.org/10.1002/jhrc.1240100809 . [all data]

Sojak, Ruman, et al., 1987
Sojak, L.; Ruman, J.; Janak, J., Characterization of Monoalkylcyclopentadiens by Retention-Structure Correlation in Capillary Gas Chromatography, J. Chromatogr., 1987, 391, 79-87, https://doi.org/10.1016/S0021-9673(01)94306-7 . [all data]

Bredael, 1982
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Notes

Go To: Top, Phase change data, Gas phase ion energetics data, Gas Chromatography, References

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  Tboil	Boiling point
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  ΔfusH	Enthalpy of fusion
  ΔfusS	Entropy of fusion
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔvapH	Enthalpy of vaporization
  ΔvapH°	Enthalpy of vaporization at standard conditions

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