Benzyne

• Formula: C₆H₄
• Molecular weight: 76.0960
• IUPAC Standard InChI: InChI=1S/C6H4/c1-2-4-6-5-3-1/h1-4H Copy

  
• IUPAC Standard InChIKey: KLYCPFXDDDMZNQ-UHFFFAOYSA-N Copy
• CAS Registry Number: 462-80-6
• 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:
  • Gas phase thermochemistry data
  • Gas phase ion energetics data
  • Vibrational and/or electronic energy levels
  • References
  • Notes
• Other data available:
  • Reaction thermochemistry data
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Gas Phase Kinetics Database
• Options:
  • Switch to calorie-based units

Gas phase thermochemistry data

Go To: Top, Gas phase ion energetics data, Vibrational and/or electronic energy levels, 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: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Vibrational and/or electronic energy levels, 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

Data compiled as indicated in comments:
B - John E. Bartmess
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
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 C₆H₄⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

De-protonation reactions

 +  =

By formula: C₆H₃^- + H⁺ = C₆H₄

Vibrational and/or electronic energy levels

Go To: Top, Gas phase thermochemistry 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: Marilyn E. Jacox

State:   ?

State:   ?

State:   ?

State:   ?

State:   a

State:   X

Additional references: Jacox, 1994, page 386; Jacox, 2003, page 364; Brown, Godfrey, et al., 1986; Robertson, Godfrey, et al., 2003; Kukolich, Tanjaroon, et al., 2003; Kukolich, McCarthy, et al., 2004

Notes

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Vibrational and/or electronic energy levels, Notes

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

Riveros, Ingeman, et al., 1991
Riveros, J.M.; Ingeman, S.; Nibbering, N.M.M., Formation of gas-phase solvated Br-and I- ion/molecule reactions of halobenzenes. Revised heat of formation of benzyne, J. Am. Chem. Soc., 1991, 113, 1053. [all data]

Wenthold, Paulino, et al., 1991
Wenthold, P.G.; Paulino, J.A.; Squires, R.R., The absolute heats of formation of o-,m-, and p-benzyne, J. Am. Chem. Soc., 1991, 113, 7414-7415. [all data]

Pollack and Hehre, 1980
Pollack, S.K.; Hehre, W.J., Determination of the heat of formation of ortho-benzyne by ion cyclotron resonance spectroscopy, Tetrahedron Lett., 1980, 21, 2483-2486. [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]

Wenthold, Squires, et al., 1998
Wenthold, P.G.; Squires, R.R.; Lineberger, W.C., Ultraviolet photoelectron spectroscopy of the o-, m-, and p-benzyne negative ions. Electron affinities and singlet-triplet splittings for o-, m-, and p-benzyne, J. Am. Chem. Soc., 1998, 120, 21, 5279-5290, https://doi.org/10.1021/ja9803355 . [all data]

Wenthold, Hu, et al., 1996
Wenthold, P.G.; Hu, J.; Squires, R.R., o-, m-, and p-Benzyne Negative Ions in the Gas Phase: Synthesis, Authentication, and Thermochemistry, J. Am. Chem. Soc., 1996, 118, 47, 11865, https://doi.org/10.1021/ja960663+ . [all data]

Leopold, Miller, et al., 1986
Leopold, D.G.; Miller, A.G.; Lineberger, W.C., Determination of the singlet-triplet splitting and electron affinity of, o-benzyne by negative ion photoelectron spectroscopy, J. Am. Chem. Soc., 1986, 108, 1379. [all data]

Zhang and Chen, 1992
Zhang, X.; Chen, P., Photoelectron spectrum of o-benzyne. Ionization potentials as a measure of singlet-triplet gaps, J. Am. Chem. Soc., 1992, 114, 3147. [all data]

Dewar and Tien, 1985
Dewar, M.J.S.; Tien, T.-P., Photoelectron spectrum of benzyne, J. Chem. Soc., Chem. Commun., 1985, 1243. [all data]

Rosenstock, Stockbauer, et al., 1980
Rosenstock, H.M.; Stockbauer, R.; Parr, A.C., Photoelectron-photoion coincidence study of benzonitrile, J. Chim. Phys., 1980, 77, 745. [all data]

Grutzmacher and Hubner, 1969
Grutzmacher, H.-F.; Hubner, J., Massenspektrometrie instabiler molekule. III: Nachweis und untersuchungen zur stabilitat chlorsubstituierter dehydrobenzole in der gasphase, Org. Mass Spectrom., 1969, 2, 649. [all data]

Grutzmacher and Lohmann, 1967
Grutzmacher, H.-F.; Lohmann, J., Massenspektrometrie instabiler organischer Molekule. I. Ionisations-potential und Bildungsenthalpie von Dehydrobenzol, Ann. Chem., 1967, 705, 81. [all data]

Guo and Grabowski, 1991
Guo, Y.L.; Grabowski, J.J., Reactions of the Benzyne Radical Anion in the Gas Phase, the Acidity of the Phenyl Radical, and the Heat of Formation of ortho-Benzyne, J. Am. Chem. Soc., 1991, 113, 16, 5923, https://doi.org/10.1021/ja00016a001 . [all data]

Gronert and DePuy, 1989
Gronert, S.; DePuy, C.H., The Dehydrophenyl Anion and the Gas Phase Ion Chemistry of Benzyne, J. Am. Chem. Soc., 1989, 111, 26, 9253, https://doi.org/10.1021/ja00208a032 . [all data]

Munzel and Schweig, 1988
Munzel, N.; Schweig, A., UV/VIS absorption spectrum, geometry and electronic structure of transient o-benzyne, Chem. Phys. Lett., 1988, 147, 2-3, 192, https://doi.org/10.1016/0009-2614(88)85082-6 . [all data]

Simon, Munzel, et al., 1990
Simon, J.G.G.; Munzel, N.; Schweig, A., Matrix isolation photochemistry: photoequilibrium between transient o-benzyne, carbon monoxide and transient cyclopentadienylideneketene in an argon matrix, Chem. Phys. Lett., 1990, 170, 2-3, 187, https://doi.org/10.1016/0009-2614(90)87113-6 . [all data]

Radziszewski, Hess, et al., 1992
Radziszewski, J.G.; Hess, B.A., Jr.; Zahradnik, R., Infrared spectrum of o-benzyne: experiment and theory, J. Am. Chem. Soc., 1992, 114, 1, 52, https://doi.org/10.1021/ja00027a007 . [all data]

Leopold, Stevens-Miller, et al., 1986
Leopold, D.G.; Stevens-Miller, A.E.; Linebergr, W.C., Determination of the singlet-triplet splitting and electron affinity of o-benzyne by negative ion photoelectron spectroscopy, J. Am. Chem. Soc., 1986, 108, 7, 1379, https://doi.org/10.1021/ja00267a003 . [all data]

Wenthold, Squires, et al., 1998, 2
Wenthold, P.G.; Squires, R.R.; Lineberger, W.C., Ultraviolet Photoelectron Spectroscopy of the, J. Am. Chem. Soc., 1998, 120, 21, 5279, https://doi.org/10.1021/ja9803355 . [all data]

Dunkin and MacDonald, 1979
Dunkin, I.R.; MacDonald, J.G., J. Chem. Soc., 1979, Chem. Commun. 772. [all data]

Chapman, Mattes, et al., 1973
Chapman, O.L.; Mattes, K.; McIntosh, C.L.; Pacansky, J.; Calder, G.V.; Orr, G., Photochemical transformations. LII. Benzyne, J. Am. Chem. Soc., 1973, 95, 18, 6134, https://doi.org/10.1021/ja00799a060 . [all data]

Nam and Leroi, 1987
Nam, H.-H.; Leroi, G.E., On the vibrational spectrum of matrix isolated o-benzyne, J. Mol. Struct., 1987, 157, 1-3, 301, https://doi.org/10.1016/0022-2860(87)87100-4 . [all data]

Jacox, 1994
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules, American Chemical Society, Washington, DC, 1994, 464. [all data]

Jacox, 2003
Jacox, M.E., Vibrational and electronic energy levels of polyatomic transient molecules: supplement B, J. Phys. Chem. Ref. Data, 2003, 32, 1, 1-441, https://doi.org/10.1063/1.1497629 . [all data]

Brown, Godfrey, et al., 1986
Brown, R.D.; Godfrey, P.D.; Rodler, M., Microwave spectrum of benzyne, J. Am. Chem. Soc., 1986, 108, 6, 1296, https://doi.org/10.1021/ja00266a028 . [all data]

Robertson, Godfrey, et al., 2003
Robertson, E.G.; Godfrey, P.D.; McNaughton, D., The microwave spectrum of o-benzyne measured in a novel Stark modulated spectrometer for transient molecules, J. Mol. Spectrosc., 2003, 217, 1, 123, https://doi.org/10.1016/S0022-2852(02)00021-8 . [all data]

Kukolich, Tanjaroon, et al., 2003
Kukolich, S.G.; Tanjaroon, C.; McCarthy, M.C.; Thaddeus, P., Microwave spectrum of o-benzyne produced in a discharge nozzle, J. Chem. Phys., 2003, 119, 8, 4353, https://doi.org/10.1063/1.1593015 . [all data]

Kukolich, McCarthy, et al., 2004
Kukolich, S.G.; McCarthy, M.C.; Thaddeus, P., Molecular Structure of, J. Phys. Chem. A, 2004, 108, 14, 2645, https://doi.org/10.1021/jp031344p . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Vibrational and/or electronic energy levels, References

• Symbols used in this document:
  

  EA	Electron affinity
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  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.