Cyanogen

• Formula: C₂N₂
• Molecular weight: 52.0348
• IUPAC Standard InChI: InChI=1S/C2N2/c3-1-2-4 Copy

  
• IUPAC Standard InChIKey: JMANVNJQNLATNU-UHFFFAOYSA-N Copy
• CAS Registry Number: 460-19-5
• 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: Ethanedinitrile; Cyanogen (C2N2); Carbon nitride (C2N2); Dicyanogen; Nitriloacetonitrile; Oxalic acid dinitrile; Oxalonitrile; NCCN; Dicyan; Cyanogen gas; Carbon nitride; Cyanogene; Oxalic nitrile; Prussite; Rcra waste number P031; UN 1026; (CN)2; Oxalyl cyanide
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• Information on this page:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Phase change data
  • Henry's Law data
  • Ion clustering data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • Vibrational and/or electronic energy levels
  • 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 as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
    C_p = heat capacity (cal/mol*K)
    H° = standard enthalpy (kcal/mol)
    S° = standard entropy (cal/mol*K)
    t = temperature (K) / 1000.

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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: Eugene S. Domalski and Elizabeth D. Hearing

Constant pressure heat capacity of liquid

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:
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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

 +  = ( • )

By formula: H₄N⁺ + C₂N₂ = (H₄N⁺ • C₂N₂)

Free energy of reaction

 +  = 2

By formula: C₂N₂ + C₂F₆ = 2C₂F₃N

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:
MM - Michael M. Meot-Ner (Mautner)
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

Gas basicity at 298K

Ionization energy determinations

Appearance energy determinations

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, 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.

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Knowlton and Prosen, 1951
Knowlton, J.W.; Prosen, E.J., Heat of combustion and formation of cyanogen, J. Res. NBS, 1951, 46, 489-495. [all data]

McMorris and Badger, 1933
McMorris, J.; Badger, R.M., The heat of combustion, entropy and free energy of cyanogen gas, J. Am. Chem. Soc., 1933, 55, 1952-1957. [all data]

Wartenberg and Schutza, 1933
Wartenberg, H.V.; Schutza, H., Die verbrennungswarme des cyans, Z. Phys. Chem., 1933, 164, 386-388. [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]

Ruehrwein and Giauque, 1939
Ruehrwein, R.A.; Giauque, W.F., The entropy of cyanogen. Heat capacity and vapor pressure of solid and liquid. Heats of fusion and vaporization, J. Am. Chem. Soc., 1939, 61, 2940-2944. [all data]

Speller and Meot-Ner (Mautner), 1985
Speller, C.V.; Meot-Ner (Mautner), M., The Ionic Hydrogen Bond and Ion Solvation. 3. Bonds Involving Cyanides. Correlations with Proton Affinites, J. Phys. Chem., 1985, 81, 24, 5217, https://doi.org/10.1021/j100270a020 . [all data]

Walker, Sinke, et al., 1970
Walker, L.C.; Sinke, G.C.; Perettie, D.J.; Janz, G.J., Enthalpy of formation of trifluoroacetonitrile, J. Am. Chem. Soc., 1970, 92, 4525-4526. [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]

Milligan, Fairley, et al., 1998
Milligan, D.B.; Fairley, D.A.; Meot-Ner (Mautner), M.; McEwan, M.J., Proton affinity of cyanogen and association reactions of C2N2H+ and C2N2CH3+, Int. J. Mass Spectrom., 1998, 180, 285. [all data]

Smith, 1983
Smith, O.I., Cross sections for formation of parent and fragment ions by electron impact from C₂N₂, Int. J. Mass Spectrom. Ion Processes, 1983, 54, 55. [all data]

Baker and Turner, 1968
Baker, C.; Turner, D.W., High resolution molecular photoelectron spectroscopy. III.Acetylenes and azaacetylenes, Proc. Roy. Soc. (London), 1968, A308, 19. [all data]

Dibeler and Liston, 1967
Dibeler, V.H.; Liston, S.K., Mass-spectrometric study of photoionization. VIII.Dicyanogen and the cyanogen halides, J. Chem. Phys., 1967, 47, 4548. [all data]

Dorsch and Kallman, 1930
Dorsch, K.E.; Kallman, H., Uber die Ionisierung von Dicyan durch langsame Elektronen, Z. Phys., 1930, 60, 376. [all data]

Asbrink, Von Niessen, et al., 1980
Asbrink, L.; Von Niessen, W.; Bieri, G., 30.4-nm He(II) photoelectron spectra of organic molecules, J. Electron Spectrosc. Relat. Phenom., 1980, 21, 93. [all data]

Haney and Franklin, 1968
Haney, M.A.; Franklin, J.L., Correlation of excess energies of electron-impact dissociations with the translational energies of the products, J.Chem. Phys., 1968, 48, 4093. [all data]

Harland and McIntosh, 1985
Harland, P.W.; McIntosh, B.J., Enthalpies of formation for the isomeric ions H_xCCN⁺ and H_xCNC⁺ (x = 0-3) by monochromatic electron impact on C₂N₂, CH₃CN and CH₃NC., Int. J. Mass Spectrom. Ion Processes, 1985, 67, 29. [all data]

Dibeler, Reese, et al., 1961
Dibeler, V.H.; Reese, R.M.; Franklin, J.L., Mass spectrometric study of cyanogen and cyanoacetylenes, J. Am. Chem. Soc., 1961, 83, 1813. [all data]

Notes

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

• Symbols used in this document:
  

  AE	Appearance energy
  Cp,liquid	Constant pressure heat capacity of liquid
  IE (evaluated)	Recommended ionization energy
  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  S°liquid	Entropy of liquid at standard conditions
  T	Temperature
  ΔcH°gas	Enthalpy of combustion of gas at standard conditions
  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
  ΔrS°	Entropy of reaction at standard conditions

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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