1,3-Diazine

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

  
• IUPAC Standard InChIKey: CZPWVGJYEJSRLH-UHFFFAOYSA-N Copy
• CAS Registry Number: 289-95-2
• 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: Pyrimidine; m-Diazine; Metadiazine; Miazine; 1,3-Diazabenzene; Py; Pyr
• 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
  • Gas phase ion energetics data
  • Ion clustering data
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • IR Spectrum
  • 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 by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.

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:
MS - José A. Martinho Simões
B - John E. Bartmess
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

C₁₀H₅CrNO₅ (solution) +  (solution) =  (solution) +  (solution)

By formula: C₁₀H₅CrNO₅ (solution) + CO (solution) = C₆CrO₆ (solution) + C₄H₄N₂ (solution)

 (cr) +  (l) = C₁₀H₅NO₅W (cr) +  (g)

By formula: C₆O₆W (cr) + C₄H₄N₂ (l) = C₁₀H₅NO₅W (cr) + CO (g)

C₄H₃N₂^- +  =

By formula: C₄H₃N₂^- + H⁺ = C₄H₄N₂

 (solution) +  (solution) = C₁₀H₅NO₅W (solution) +  (solution)

By formula: C₆O₆W (solution) + C₄H₄N₂ (solution) = C₁₀H₅NO₅W (solution) + CO (solution)

C₃₉H₆₈O₃P₂W (solution) +  (solution) = C₄₄H₇₁NO₃P₂W (solution) +  (g)

By formula: C₃₉H₆₈O₃P₂W (solution) + C₄H₄N₂ (solution) = C₄₄H₇₁NO₃P₂W (solution) + H₂ (g)

C₁₄H₁₀CrN₂O₄ (cr) = 2 (g) + 4 (g) +  (cr)

By formula: C₁₄H₁₀CrN₂O₄ (cr) = 2C₄H₄N₂ (g) + 4CO (g) + Cr (cr)

C₈H₆MoO₃ (solution) + 3 (solution) = C₁₈H₁₅MoN₃O₃ (solution) +  (solution)

By formula: C₈H₆MoO₃ (solution) + 3C₄H₄N₂ (solution) = C₁₈H₁₅MoN₃O₃ (solution) + C₅H₆ (solution)

 +  = C₄H₄N₃O^-

By formula: NO^- + C₄H₄N₂ = C₄H₄N₃O^-

C₉H₉CrN₃O₃ (solution) + 3 (solution) = C₁₈H₁₅CrN₃O₃ (solution) + 3 (solution)

By formula: C₉H₉CrN₃O₃ (solution) + 3C₄H₄N₂ (solution) = C₁₈H₁₅CrN₃O₃ (solution) + 3C₂H₃N (solution)

C₇H₉Cl₂NPd (solution) +  (l) = (PdCl₂(C₅H₅N)₂) (solution) +  (solution)

By formula: C₇H₉Cl₂NPd (solution) + C₄H₄N₂ (l) = (PdCl₂(C₅H₅N)₂) (solution) + C₂H₄ (solution)

C₁₀H₅NO₅W (cr) +  (g) =  (g) +  (g)

By formula: C₁₀H₅NO₅W (cr) + CO (g) = C₆O₆W (g) + C₄H₄N₂ (g)

C₁₂H₁₆CrO₅ (solution) +  (solution) =  (solution) + C₁₀H₅CrNO₅ (solution)

By formula: C₁₂H₁₆CrO₅ (solution) + C₄H₄N₂ (solution) = C₇H₁₆ (solution) + C₁₀H₅CrNO₅ (solution)

C₃₉H₆₆MoO₃P₃ (solution) +  (solution) = C₄₄H₇₁MoNO₃P₂ (solution)

By formula: C₃₉H₆₆MoO₃P₃ (solution) + C₄H₄N₂ (solution) = C₄₄H₇₁MoNO₃P₂ (solution)

 (cr) + 3 (g) = C₁₈H₁₅MoN₃O₃ (cr) + 3 (g)

By formula: C₆MoO₆ (cr) + 3C₄H₄N₂ (g) = C₁₈H₁₅MoN₃O₃ (cr) + 3CO (g)

 (cr) + 3 (g) = C₁₈H₁₅N₃O₃W (g) + 3 (g)

By formula: C₆O₆W (cr) + 3C₄H₄N₂ (g) = C₁₈H₁₅N₃O₃W (g) + 3CO (g)

C₁₀H₅CrNO₅ (cr) +  (g) =  (g) +  (g)

By formula: C₁₀H₅CrNO₅ (cr) + CO (g) = C₆CrO₆ (g) + C₄H₄N₂ (g)

C₁₀H₅MoNO₅ (cr) +  (g) =  (g) +  (g)

By formula: C₁₀H₅MoNO₅ (cr) + CO (g) = C₆MoO₆ (g) + C₄H₄N₂ (g)

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

Gas phase ion energetics 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 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
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

Ion clustering 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:
RCD - Robert C. Dunbar
B - John E. Bartmess

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = C₄H₄N₃O^-

By formula: NO^- + C₄H₄N₂ = C₄H₄N₃O^-

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

 +  = ( • )

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

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, Gas phase ion energetics data, Ion clustering data, 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.

Nabavian, Sabbah, et al., 1977
Nabavian, P.M.; Sabbah, R.; Chastel, R.; Laffitte, M., Thermodynamique de composes azotes. II. Etude thermochimique des acides aminobenzoiques, de la pyrimidine, de l'uracile et de la thymine., J. Chim. Phys., 1977, 74, 115-126. [all data]

Pedley, Naylor, et al., 1986
Pedley, J.B.; Naylor, R.D.; Kirby, S.P., Thermochemical Data of Organic Compounds, Chapman and Hall, New York, 1986, 1-792. [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]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [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]

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Wovkulich, M.J.; Atwood, J.D., J. Organometal. Chem., 1980, 184, 77. [all data]

Dennenberg and Darensbourg, 1972
Dennenberg, R.J.; Darensbourg, D.J., Inorg. Chem., 1972, 11, 72. [all data]

Graham and Angelici, 1967
Graham, J.R.; Angelici, R.J., Inorg. Chem., 1967, 6, 2082. [all data]

Nakashima and Adamson, 1982
Nakashima, M.; Adamson, A.W., J. Phys. Chem., 1982, 86, 2905. [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]

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]

Gonzalez, Zhang, et al., 1988
Gonzalez, A.A.; Zhang, K.; Nolan, S.P.; Lopez de la Vega, R.; Mukerjee, S.L.; Hoff, C.D., Organometallics, 1988, 7, 2429. [all data]

Adedeji, Connor, et al., 1978
Adedeji, F.A.; Connor, J.A.; Demain, C.P.; Martinho Simões, J.A.; Skinner, H.A.; Zafarani- Moattar, M.T., J. Organometal. Chem., 1978, 149, 333. [all data]

Nolan, Hoff, et al., 1985
Nolan, S.P.; Hoff, C.D.; Landrum, J.T., J. Organometal. Chem., 1985, 282, 357. [all data]

Le Barbu, Schiedt, et al., 2002
Le Barbu, K.; Schiedt, J.; Weinkauf, R.; Schlag, E.W.; Nilles, J.M.; Xu, S.J.; Thomas, O.C.; Bowen, K.H., Microsolvation of small anions by aromatic molecules: An exploratory study, J. Chem. Phys., 2002, 116, 22, 9663-9671, https://doi.org/10.1063/1.1475750 . [all data]

Mukerjee, Lang, et al., 1992
Mukerjee, S.L.; Lang, R.F.; Ju, T.; Kiss, G.; Hoff, C.D.; Nolan, S.P., Inorg. Chem., 1992, 31, 4885. [all data]

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Partenheimer, W.; Durham, B., J. Am. Chem. Soc., 1974, 96, 3800. [all data]

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Meester, Vriends, et al., 1976
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Amunugama and Rodgers, 2001
Amunugama, R.; Rodgers, M.T., Periodic Trends in the Binding of Metal Ions to Pyrimidine Studied by Threshold Collision-Induced Dissociation and Density Functional Theory, J. Phys. Chem. A, 2001, 105, 43, 9883, https://doi.org/10.1021/jp010663i . [all data]

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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]

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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]

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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]

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Asbrink, L.; Fridh, C.; Jonsson, B.O.; Lindholm, E., Rydberg series in small molecules. XVI. Photoelectron, UV, mass and electron impact spectra of pyrimidine, Int. J. Mass Spectrom. Ion Phys., 1972, 8, 215. [all data]

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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]

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Notes

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• Symbols used in this document:
  

  AE	Appearance energy
  EA	Electron affinity
  IE (evaluated)	Recommended ionization energy
  Tboil	Boiling point
  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
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔrS°	Entropy of reaction at standard conditions
  ΔvapH°	Enthalpy of vaporization 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.
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