Ethynyl radical

• Formula: C₂H
• Molecular weight: 25.0293
• IUPAC Standard InChI: InChI=1S/C2H/c1-2/h1H Copy

  
• IUPAC Standard InChIKey: XEHVFKKSDRMODV-UHFFFAOYSA-N Copy
• CAS Registry Number: 2122-48-7
• 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.
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Ion clustering data
  • Vibrational and/or electronic energy levels
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Gas Phase Kinetics Database
• Options:
  • Switch to SI units

Data at NIST subscription sites:

• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.

Reaction thermochemistry data

Go To: Top, 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: John E. Bartmess

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

(C₂H₂^- • 4294967295) +  = C₂H₂^-

By formula: (C₂H₂^- • 4294967295C₂H) + C₂H = C₂H₂^-

Gas phase ion energetics data

Go To: Top, Reaction thermochemistry data, 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
LL - Sharon G. Lias and Joel F. Liebman
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi

View reactions leading to C₂H⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

Anion protonation reactions

C₂H^- +  =

By formula: C₂H^- + H⁺ = C₂H₂

References

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, Notes

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

Ervin, Gronert, et al., 1990
Ervin, K.M.; Gronert, S.; Barlow, S.E.; Gilles, M.K.; Harrison, A.G.; Bierbaum, V.M.; DePuy, C.H.; Lin, W.C., Bonds Strengths of Ethylene and Acetylene, J. Am. Chem. Soc., 1990, 112, 15, 5750, https://doi.org/10.1021/ja00171a013 . [all data]

Kiefer, Sidhu, et al., 1989
Kiefer, J.H.; Sidhu, S.S.; Kumaran, S.S.; Irdan, E.A., RRKM Model of C2H4 Dissociation: Heat of Formation of Vinylidene, Chem. Phys. Lett., 1989, 159, 1, 32, https://doi.org/10.1016/S0009-2614(89)87448-2 . [all data]

Guo and Grabowski, 1990
Guo, Y.; Grabowski, J.J., Gas Phase Ion Chemistry of the Vinylidene Radical Anion and the Acidity of the Vinyl Radical, Int. J. Mass Spectrom. Ion Proc., 1990, 97, 3, 253, https://doi.org/10.1016/0168-1176(90)85003-K . [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]

Zhou, Garand, et al., 2007
Zhou, J.; Garand, E.; Neumark, D.M., Vibronic structure in C2H and C2D from anion slow electron velocity-map imaging spectroscopy, J. Chem. Phys., 2007, 127, 11, 114313, https://doi.org/10.1063/1.2768932 . [all data]

Ervin and Lineberger, 1991
Ervin, K.M.; Lineberger, W.C., Photoelectron Spectra of C2- and C2H-, J. Phys. Chem., 1991, 95, 3, 1167, https://doi.org/10.1021/j100156a026 . [all data]

Taylor, Xu, et al., 1998
Taylor, T.R.; Xu, C.S.; Neumark, D.M., Photoelectron spectra of the C2nH- (n=1-4) and C2nD- (n=1-3) anions, J. Chem. Phys., 1998, 108, 24, 10018-10026, https://doi.org/10.1063/1.476462 . [all data]

Janousek, Brauman, et al., 1979
Janousek, B.K.; Brauman, J.I.; Simons, J., An experimental and theoretical determination of the electron affinity of the enhynyl radical HC₂, J. Chem. Phys., 1979, 71, 2057. [all data]

Thynne and MacNiel, 1971
Thynne, J.C.J.; MacNiel, K.A.G., Negative ion formation by ethylene and 1,1-difluoroethylene, J. Phys. Chem., 1971, 75, 2584. [all data]

Feldman, 1970
Feldman, D., Photoablosung von Elektronen bei einigen Stabilen Negativen Ionen, Z. Naturfor., 1970, 25A, 621. [all data]

Locht and Momigny, 1970
Locht, R.; Momigny, J., Mass Spectrometric Determination of the Electron Affinities of Radicals, Chem. Phys. Lett., 1970, 6, 4, 273, https://doi.org/10.1016/0009-2614(70)85072-2 . [all data]

Trepka and Neuert, 1963
Trepka, L.v.; Neuert, H., Uber die Entstehenung von Negativen Ionen aus einigen Kohlenwasserstoffen und Alkoholen durch Elektronenstoss, Z. Naturfor., 1963, 18A, 1295. [all data]

Page and Goode, 1969
Page, F.M.; Goode, G.C., Negative Ions and the Magnetron., Wiley, NY, 1969. [all data]

Norwood and Ng, 1989
Norwood, K.; Ng, C.Y., A state-selected study of the unimolecular decompoisition of C₂H₂⁺(A,B) using the photoion photoelectron coincidence method, J. Chem. Phys., 1989, 91, 2898. [all data]

Lias, Bartmess, et al., 1988
Lias, S.G.; Bartmess, J.E.; Liebman, J.F.; Holmes, J.L.; Levin, R.D.; Mallard, W.G., Gas-phase ion and neutral thermochemistry, J. Phys. Chem. Ref. Data, Suppl. 1, 1988, 17, 1-861. [all data]

Ono and Ng, 1981
Ono, Y.; Ng, C.Y., The heat of formation of C₂H⁺, J. Chem. Phys., 1981, 74, 6985. [all data]

Okabe and Dibeler, 1973
Okabe, H.; Dibeler, V.H., Photon impact studies of C₂HCN and CH₃CN in the vacuum ultraviolet; heats of formation of C₂H and CH₃CN, J. Chem. Phys., 1973, 59, 2430. [all data]

Dibeler, Walker, et al., 1973
Dibeler, V.H.; Walker, J.A.; McCulloh, K.E., Observations on hot bands in the molecular and dissociative photoionization of acetylene and the heat of formation of the ethynyl ion, J. Chem. Phys., 1973, 59, 2264. [all data]

Wyatt and Stafford, 1972
Wyatt, J.R.; Stafford, F.E., Mass spectrometric determination of the heat of formation of ethynyl radical, C₂H, and of some related species, J. Phys. Chem., 1972, 76, 1913. [all data]

Notes

Go To: Top, Reaction thermochemistry data, Gas phase ion energetics data, References

• Symbols used in this document:
  

  EA	Electron affinity
  IE (evaluated)	Recommended ionization 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
• The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
• Customer support for NIST Standard Reference Data products.