2-Butyne

• Formula: C₄H₆
• Molecular weight: 54.0904
• IUPAC Standard InChI: InChI=1S/C4H6/c1-3-4-2/h1-2H3 Copy

  
• IUPAC Standard InChIKey: XNMQEEKYCVKGBD-UHFFFAOYSA-N Copy
• CAS Registry Number: 503-17-3
• Chemical structure:
  This structure is also available as a 2d Mol file or as a computed 3d SD file
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• Other names: But-2-yne; Dimethylacetylene; CH3C≡CCH3; Crotonylene; UN 1144
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• Information on this page:
  • Reaction thermochemistry data
  • IR Spectrum
  • Vibrational and/or electronic energy levels
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Gas phase ion energetics data
  • Mass spectrum (electron ionization)
  • Gas Chromatography
• Data at other public NIST sites:
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  • Gas Phase Kinetics Database
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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 as indicated in comments:
B - John E. Bartmess
ALS - 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

C₄H₅^- +  =

By formula: C₄H₅^- + H⁺ = C₄H₆

2 +  =

By formula: 2H₂ + C₄H₆ = C₄H₁₀

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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Additional Data

Vibrational and/or electronic energy levels

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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: Takehiko Shimanouchi

Symmetry:   D'_3h     Symmetry Number σ = 6

Source: Shimanouchi, 1972

Notes

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.

Gal, Decouzon, et al., 2001
Gal, J.F.; Decouzon, M.; Maria, P.C.; Gonzalez, A.I.; Mo, O.; Yanez, M.; El Chaouch, S.; Guillemin, J.C., Acidity trends in alpha,beta-unsaturated alkanes, silanes, germanes, and stannanes, J. Am. Chem. Soc., 2001, 123, 26, 6353-6359, https://doi.org/10.1021/ja004079j . [all data]

Conn, Kistiakowsky, et al., 1939
Conn, J.B.; Kistiakowsky, G.B.; Smith, E.A., Heats of organic reactions. VIII. Some further hydrogenations, including those of some acetylenes, J. Am. Chem. Soc., 1939, 61, 1868-1876. [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]

Shimanouchi, 1972
Shimanouchi, T., Tables of Molecular Vibrational Frequencies Consolidated Volume I, National Bureau of Standards, 1972, 1-160. [all data]

Notes

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• Symbols used in this document:
  

  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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