Pyrazine

• Formula: C₄H₄N₂
• Molecular weight: 80.0880
• IUPAC Standard InChI: InChI=1S/C4H4N2/c1-2-6-4-3-5-1/h1-4H Copy

  
• IUPAC Standard InChIKey: KYQCOXFCLRTKLS-UHFFFAOYSA-N Copy
• CAS Registry Number: 290-37-9
• 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: p-Diazine; Paradiazine; Piazine; 1,4-Diazabenzene; 1,4-Diazine
• 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
  • 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
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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Phase change 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 as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
DH - Eugene S. Domalski and Elizabeth D. Hearing

Reduced pressure boiling point

Enthalpy of vaporization

Enthalpy of sublimation

Enthalpy of fusion

Enthalpy of phase transition

Entropy of phase transition

Gas phase ion energetics data

Go To: Top, Phase change 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

Data compiled as indicated in comments:
B - John E. Bartmess
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 C₄H₄N₂⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

C₄H₃N₂^- +  =

By formula: C₄H₃N₂^- + H⁺ = C₄H₄N₂

References

Go To: Top, Phase change 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.

Aldrich Chemical Company Inc., 1990
Aldrich Chemical Company Inc., Catalog Handbook of Fine Chemicals, Aldrich Chemical Company, Inc., Milwaukee WI, 1990, 1. [all data]

Anderson and Shimanskaya, 1969
Anderson, A.A.; Shimanskaya, M.V., Gas-Liquid Chromatography of some Aliphatic and Heterocyclic Polyfunctional Amines: II. Solution Thermodyn. of Amines in Fix. Phas., Latv. PSR Zinat. Akad. Vestis, Kim. Ser., 1969, No. 5, 527. [all data]

Lecat, 1947
Lecat, M., Some azeotropes of which one constituant is heterocyclic nitrogen, Ann. Soc. Sci. Bruxelles, Ser. 1, 1947, 61, 73. [all data]

Bougeard, LeCalve, et al., 1978
Bougeard, D.; LeCalve, N.; Novak, A.; Bachanh, N., Phase transitions of pyrazine., Mol. Cryst. Liq. Cryst., 1978, 44, 113. [all data]

Bruhl, 1897
Bruhl, J.W., Spectrochemistry of nitrogen containing compounds V, Z. Phys. Chem., Stoechiom. Verwandtschaftsl., 1897, 22, 373. [all data]

Lipkind and Chickos, 2009
Lipkind, Dmitri; Chickos, James S., An examination of the vaporization enthalpies and vapor pressures of pyrazine, pyrimidine, pyridazine, and 1,3,5-triazine, Struct Chem, 2009, 20, 1, 49-58, https://doi.org/10.1007/s11224-008-9389-5 . [all data]

Lipkind and Chickos, 2009, 2
Lipkind, D.; Chickos, J.S., , Abstract from 38th Great Lakes Regional Meeting of the American Chemical Society, May 13-16, Chicago, IL, 2009, GLRM-275. [all data]

Tjebbes, 1962
Tjebbes, J., The heats of combustion and formation of the three diazines and their resonance energies, Acta Chem. Scand., 1962, 16, 916-921. [all data]

Weast and Grasselli, 1989
CRC Handbook of Data on Organic Compounds, 2nd Editon, Weast,R.C and Grasselli, J.G., ed(s)., CRC Press, Inc., Boca Raton, FL, 1989, 1. [all data]

Steele, Chirico, et al., 2002
Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A., Measurements of Vapor Pressure, Heat Capacity, and Density along the Saturation Line for γ-Caprolactam, Pyrazine, 1,2-Propanediol, Triethylene Glycol, Phenyl Acetylene, and Diphenyl Acetylene, J. Chem. Eng. Data, 2002, 47, 4, 689-699, https://doi.org/10.1021/je010085z . [all data]

Sakoguchi, Ueoka, et al., 1995
Sakoguchi, Akihiro; Ueoka, Ryuichi; Kato, Yasuo; Arai, Yasuhiko, Vapor Pressures of Alkylpyridines and Alkylpyrazines., KAGAKU KOGAKU RONBUNSHU, 1995, 21, 1, 219-223, https://doi.org/10.1252/kakoronbunshu.21.219 . [all data]

Chirico, Knipmeyer, et al., 2003
Chirico, R.D.; Knipmeyer, S.E.; Steele, W.V., Heat capacities, enthalpy increments, and derived thermodynamic functions for pyrazine between the temperatures 5K and 380K, The Journal of Chemical Thermodynamics, 2003, 35, 7, 1059-1072, https://doi.org/10.1016/S0021-9614(03)00041-7 . [all data]

Bougeard, Calve, et al., 1978
Bougeard, D.; Calve, N. Le; Novak, A.; Nguyen-ba-chanh, A., Phase Transitions of Pyrazine, GMCL, 1978, 44, 1, 113-123, https://doi.org/10.1080/15421407808083935 . [all data]

Boyd, Comper, et al., 1979
Boyd, R.K.; Comper, J.; Ferguson, G., Entropy changes and structural implications for crystalline phases of pyrazine, Can. J. Chem., 1979, 57, 3056-3060. [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]

Nenner and Schultz, 1975
Nenner, I.; Schultz, G.J., Temporary negative ions and electron affinities of benzene and N-heterocyclic molecules: Pyridine, pyridazine, pyrimidine, pyrazine, and s-triazine, J. Chem. Phys., 1975, 62, 1747. [all data]

Piancastelli, Keller, et al., 1983
Piancastelli, M.N.; Keller, P.R.; Taylor, J.W.; Grimm, F.A.; Carlson, T.A., Angular distribution parameter as a function of photon energy for some mono- and diazabenzenes and its use for orbital assignment, J. Am. Chem. Soc., 1983, 105, 4235. [all data]

Scheps, Florida, et al., 1972
Scheps, R.; Florida, D.; Rice, S.A., Comments on the Rydberg spectrum of pyrazine, J. Mol. Spectrosc., 1972, 44, 1. [all data]

Gleiter, Heilbronner, et al., 1972
Gleiter, R.; Heilbronner, E.; Hornung, V., Photoelectron spectra of azabenzenes azanaphthalenes: I. Pyridine, diazines s-triazine and s-tetrazine, Helv. Chim. Acta, 1972, 55, 255. [all data]

Asbrink, Lindholm, et al., 1970
Asbrink, L.; Lindholm, E.; Edqvist, O., Jahn-Teller effect in the vibrational structure of the photoelectron spectrum of benzene, Chem. Phys. Lett., 1970, 5, 609. [all data]

Eland, 1969
Eland, J.H.D., Photoelectron spectra of conjugated hydrocarbons and heteromolecules, Intern. J. Mass Spectrom. Ion Phys., 1969, 2, 471. [all data]

Dewar and Worley, 1969
Dewar, M.J.S.; Worley, S.D., Photoelectron spectra of molecules. II.The ionization potentials of azabenzenes and azanaphthalenes, J. Chem. Phys., 1969, 51, 263. [all data]

Yencha and El-Sayed, 1968
Yencha, A.J.; El-Sayed, M.A., Lowest ionization potentials of some nitrogen heterocyclics, J. Chem. Phys., 1968, 48, 3469. [all data]

Parkin and Innes, 1965
Parkin, J.E.; Innes, K.K., The vacuum ultraviolet spectra of pyrazine, pyrimidine, and pyridazine vapors. Part I. Spectra between 1550 A and 2000 A, J. Mol. Spectry., 1965, 15, 407. [all data]

Suffolk, 1974
Suffolk, R.J., The photoelectron spectra of the perfluorodiazines, J. Electron Spectrosc. Relat. Phenom., 1974, 3, 53. [all data]

Gleiter, Heilbronner, et al., 1970
Gleiter, R.; Heilbronner, E.; Hornung, V., Lone pair interaction in pyridazine, pyrimidine, and pyrazine, Angew. Chem. Int. Ed. Engl., 1970, 9, 901. [all data]

Momigny, Urbain, et al., 1965
Momigny, J.; Urbain, J.; Wankenne, H., Les effets de l'impact electronique sur la pyridine et les diazines isomeres, Bull. Soc. Roy. Sci. Liege, 1965, 34, 337. [all data]

Meot-ner and Kafafi, 1988
Meot-ner, M.; Kafafi, S.A., Carbon Acidities of Aromatic Compounds, J. Am. Chem. Soc., 1988, 110, 19, 6297, https://doi.org/10.1021/ja00227a003 . [all data]

Kiefer, Zhang, et al., 1997
Kiefer, J.H.; Zhang, Q.; Kern, R.D.; Yao, J.; Jursic, B., Pyrolysis of Aromatic Azines: Pyrazine, Pyrimidine, and Pyridine, J. Phys. Chem. A, 1997, 101, 38, 7061, https://doi.org/10.1021/jp970211z . [all data]

Wren, Vogelhuber, et al., 2012
Wren, S.W.; Vogelhuber, K.M.; Garver, J.M.; Kato, S.; Sheps, L.; Bierbaum, V.M.; Lineberger, W.C., C-H Bond Strengths and Acidities in Aromatic Systems: Effects of Nitrogen Incorporation in Mono-, Di-, and Triazines, J. Am. Chem. Soc., 2012, 134, 15, 6584-6595, https://doi.org/10.1021/ja209566q . [all data]

Notes

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

• Symbols used in this document:
  

  AE	Appearance energy
  EA	Electron affinity
  Tboil	Boiling point
  Tfus	Fusion (melting) point
  ΔHtrs	Enthalpy of phase transition
  ΔStrs	Entropy of phase transition
  ΔfusH	Enthalpy of fusion
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔsubH	Enthalpy of sublimation
  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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