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:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Gas phase ion energetics data
  • Ion clustering data
  • UV/Visible spectrum
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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Gas phase 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 by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Condensed phase 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:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Constant pressure heat capacity of solid

Phase change 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:
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

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
RCD - Robert C. Dunbar

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

C₄H₃N₂^- +  =

By formula: C₄H₃N₂^- + H⁺ = C₄H₄N₂

3 +  =

By formula: 3H₂ + C₄H₄N₂ = C₄H₁₀N₂

 +  = ( • )

By formula: Li⁺ + C₄H₄N₂ = (Li⁺ • C₄H₄N₂)

 +  = ( • )

By formula: Na⁺ + C₄H₄N₂ = (Na⁺ • C₄H₄N₂)

 +  = ( • )

By formula: K⁺ + C₄H₄N₂ = (K⁺ • C₄H₄N₂)

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: Coblentz Society, Inc.

Condensed Phase Spectrum

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Notice: Except where noted, spectra from this collection were measured on dispersive instruments, often in carefully selected solvents, and hence may differ in detail from measurements on FTIR instruments or in other chemical environments. More information on the manner in which spectra in this collection were collected can be found here.

Notice: Concentration information is not available for this spectrum and, therefore, molar absorptivity values cannot be derived.

Additional Data

Mass spectrum (electron ionization)

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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

Spectrum

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Additional Data

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), Notes

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

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]

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]

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]

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]

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]

Hafelinger and Steinmann, 1977
Hafelinger, G.; Steinmann, L., Heat of hydrogenation of compounds containing isolated and conjugted C=N bouble bonds, Angew. Chem. Int. Ed. Engl., 1977, 16, 47-48. [all data]

Amunugama and Rodgers, 2000
Amunugama, R.; Rodgers, M.T., Absolute Alkali Metal Ion Binding Affinities of Several Azines Determined by Threshold Collision-Induced Dissociation and Ab Initio Theory, Int. J. Mass Spectrom., 2000, 195/196, 439, https://doi.org/10.1016/S1387-3806(99)00145-1 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, IR Spectrum, Mass spectrum (electron ionization), References

• Symbols used in this document:
  

  Cp,solid	Constant pressure heat capacity of solid
  Tboil	Boiling point
  Tfus	Fusion (melting) point
  ΔHtrs	Enthalpy of phase transition
  ΔStrs	Entropy of phase transition
  ΔcH°liquid	Enthalpy of combustion of liquid at standard conditions
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔfH°liquid	Enthalpy of formation of liquid at standard conditions
  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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