1,2-Butadiene

• Formula: C₄H₆
• Molecular weight: 54.0904
• IUPAC Standard InChI: InChI=1S/C4H6/c1-3-4-2/h4H,1H2,2H3 Copy

  
• IUPAC Standard InChIKey: QNRMTGGDHLBXQZ-UHFFFAOYSA-N Copy
• CAS Registry Number: 590-19-2
• 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: Allene, methyl-; Methylallene; CH2=C=CHCH3; Buta-1,2-diene
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• Information on this page:
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • Gas Chromatography
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Computational Chemistry Comparison and Benchmark Database
  • Gas Phase Kinetics Database
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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

Data compiled as indicated in comments:
B - John E. Bartmess
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 C₄H₆⁺ (ion structure unspecified)

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

C₄H₅^- +  =

By formula: C₄H₅^- + H⁺ = C₄H₆

References

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

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]

Beez, Bieri, et al., 1973
Beez, M.; Bieri, G.; Bock, H.; Heilbronner, E., The ionization potentials of butadiene, hexatriene, andtheir methyl derivatives: evidence for through space interaction between double bond π-orbitals and non-bonded pseudo-π orbitals of methyl groups?, Helv. Chim. Acta, 1973, 56, 1028. [all data]

Parr and Elder, 1968
Parr, A.C.; Elder, F.A., Photoionization of 1,3butadiene, 1,2-butadiene, allene, and propyne, J. Chem. Phys., 1968, 49, 2659. [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]

White, Carlson, et al., 1974
White, R.M.; Carlson, T.A.; Spears, D.P., Angular distribution of the photoelectron spectra for ethylene, propylene, butene and butadiene, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 59. [all data]

Brogli, Crandall, et al., 1973
Brogli, F.; Crandall, J.K.; Heilbronner, E.; Kloster-Jensen, E.; Sojka, S.A., The photoelectron spectra of methyl-substituted allenes and of tetramethyl-bisallenyl, J. Electron Spectrosc. Relat. Phenom., 1973, 2, 455. [all data]

Collin and Lossing, 1957
Collin, J.; Lossing, F.P., Ionization and dissociation of allene, propyne, 1-butyne, and 1,2- and 1,3-butadienes by electron impact; the C₃H₃⁺ ion, J. Am. Chem. Soc., 1957, 79, 5848. [all data]

Notes

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• Symbols used in this document:
  

  AE	Appearance energy
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions

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