Pyridine

• Formula: C₅H₅N
• Molecular weight: 79.0999
• IUPAC Standard InChI: InChI=1S/C5H5N/c1-2-4-6-5-3-1/h1-5H Copy

  
• IUPAC Standard InChIKey: JUJWROOIHBZHMG-UHFFFAOYSA-N Copy
• CAS Registry Number: 110-86-1
• 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.
• Isotopologues:
  • Pyridine-D5-
• Other names: Azabenzene; Azine; NCI-C55301; Piridina; Pirydyna; Pyridin; Rcra waste number U196; UN 1282; Pyr; CP 32; NSC 406123
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Henry's Law 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
  • X-ray Photoelectron Spectroscopy Database, version 5.0
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Reaction thermochemistry 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:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
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

C₅H₄N^- +  =

By formula: C₅H₄N^- + H⁺ = C₅H₅N

C₅H₆N⁺ +  = (C₅H₆N⁺ • )

By formula: C₅H₆N⁺ + C₅H₅N = (C₅H₆N⁺ • C₅H₅N)

 + 3 =

By formula: C₅H₅N + 3H₂ = C₅H₁₁N

 +  = ( • )

By formula: Cl^- + C₅H₅N = (Cl^- • C₅H₅N)

(C₅H₆N⁺ • 2) +  = (C₅H₆N⁺ • 3)

By formula: (C₅H₆N⁺ • 2C₅H₅N) + C₅H₅N = (C₅H₆N⁺ • 3C₅H₅N)

 +  = ( • )

By formula: Li⁺ + C₅H₅N = (Li⁺ • C₅H₅N)

 +  = ( • )

By formula: K⁺ + C₅H₅N = (K⁺ • C₅H₅N)

( • 2) +  = ( • 3)

By formula: (Ag⁺ • 2C₅H₅N) + C₅H₅N = (Ag⁺ • 3C₅H₅N)

( • 3) +  = ( • 4)

By formula: (Ag⁺ • 3C₅H₅N) + C₅H₅N = (Ag⁺ • 4C₅H₅N)

( • ) +  = ( • 2)

By formula: (Cl^- • C₅H₅N) + C₅H₅N = (Cl^- • 2C₅H₅N)

(C₅H₆N⁺ • ) +  = (C₅H₆N⁺ • 2)

By formula: (C₅H₆N⁺ • C₅H₅N) + C₅H₅N = (C₅H₆N⁺ • 2C₅H₅N)

H₂O₃^- +  +  = C₅H₇NO₃^-

By formula: H₂O₃^- + C₅H₅N + H₂O = C₅H₇NO₃^-

 +  = C₅H₅NO₂^-

By formula: O₂^- + C₅H₅N = C₅H₅NO₂^-

 +  = C₅H₅N₂O^-

By formula: NO^- + C₅H₅N = C₅H₅N₂O^-

3 +  = 3 + KClO₃

By formula: 3C₅H₅NO + ClK = 3C₅H₅N + KClO₃

3 +  = 3 + KBrO₃

By formula: 3C₅H₅NO + BrK = 3C₅H₅N + KBrO₃

 +  = ( • )

By formula: Fe⁺ + C₅H₅N = (Fe⁺ • C₅H₅N)

 +  = ( • )

By formula: Cr⁺ + C₅H₅N = (Cr⁺ • C₅H₅N)

 +  = ( • )

By formula: Ti⁺ + C₅H₅N = (Ti⁺ • C₅H₅N)

 +  = ( • )

By formula: Mn⁺ + C₅H₅N = (Mn⁺ • C₅H₅N)

 +  = ( • )

By formula: Sc⁺ + C₅H₅N = (Sc⁺ • C₅H₅N)

 +  = ( • )

By formula: Mg⁺ + C₅H₅N = (Mg⁺ • C₅H₅N)

 +  = ( • )

By formula: V⁺ + C₅H₅N = (V⁺ • C₅H₅N)

 +  = ( • )

By formula: Ni⁺ + C₅H₅N = (Ni⁺ • C₅H₅N)

 +  = ( • )

By formula: Al⁺ + C₅H₅N = (Al⁺ • C₅H₅N)

 +  = ( • )

By formula: Zn⁺ + C₅H₅N = (Zn⁺ • C₅H₅N)

 +  = ( • )

By formula: Co⁺ + C₅H₅N = (Co⁺ • C₅H₅N)

 +  = ( • )

By formula: Cu⁺ + C₅H₅N = (Cu⁺ • C₅H₅N)

 +  = ( • )

By formula: Na⁺ + C₅H₅N = (Na⁺ • C₅H₅N)

Gas phase ion energetics data

Go To: Top, Reaction thermochemistry 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
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
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

Proton affinity at 298K

Protonation entropy at 298K

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

C₅H₄N^- +  =

By formula: C₅H₄N^- + H⁺ = C₅H₅N

References

Go To: Top, 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.

Schafman and Wenthold, 2007
Schafman, B.S.; Wenthold, P.G., Regioselectivity of pyridine deprotonation in the gas phase, J. Org. Chem., 2007, 72, 5, 1645-1651, https://doi.org/10.1021/jo062117x . [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]

DePuy, Kass, et al., 1988
DePuy, C.H.; Kass, S.R.; Bean, G.P., Formation and Reactions of Heteroaromatic Anions in the Gas Phase, J. Org. Chem., 1988, 53, 19, 4427, https://doi.org/10.1021/jo00254a001 . [all data]

Bruins, Ferrer-Correia, et al., 1978
Bruins, A.P.; Ferrer-Correia, A.J.; Harrison, A.G.; Jennings, K.R.; Mithcum, R.K., Negative ion chemical ionization mass spectrometry of some aromatic compounds using O-. as the reagent ion, Adv. Mass Spectrom., 1978, 7, 355. [all data]

Meot-Ner (Mautner), 1992
Meot-Ner (Mautner), M., Intermolecular Forces in Organic Clusters, J. Am. Chem. Soc., 1992, 114, 9, 3312, https://doi.org/10.1021/ja00035a024 . [all data]

Meot-Ner M. and Sieck, 1983
Meot-Ner M.; Sieck, L.W., The Ionic Hydrogen Bond. 1. Sterically Hindered Bonds. Solvation and Clustering of Sterically Hindered Amines and Pyridines, J. Am. Chem. Soc., 1983, 105, 10, 2956, https://doi.org/10.1021/ja00348a005 . [all data]

Holland and Castleman, 1982
Holland, P.M.; Castleman, A.W., The Thermochemical Properties of Gas - Phase Transition Metal Ion Complexes, J. Chem. Phys., 1982, 76, 8, 4195, https://doi.org/10.1063/1.443497 . [all data]

Meot-Ner (Mautner), 1979
Meot-Ner (Mautner), M., Ion Thermochemistry of Low Volatility Compounds in the Gas Phase. II. Intrinsic Basicities and Hydrogen Bonded Dimers of Nitrogen Heterocyclics and Nucleic Bases, J. Am. Chem. Soc., 1979, 101, 9, 2396, https://doi.org/10.1021/ja00503a027 . [all data]

Hales and Herington, 1957
Hales, J.L.; Herington, E.F.G., Equilibrium between pyridine and piperidine, Trans. Faraday Soc., 1957, 53, 616-622. [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]

Burrows and King, 1935
Burrows, G.H.; King, L.A., Jr., The free energy change that accompanies hydrogenation of pyridine to piperidine, J. Am. Chem. Soc., 1935, 57, 1789-1791. [all data]

Hiraoka, Mizuse, et al., 1988
Hiraoka, K.; Mizuse, S.; Yamabe, S., Determination of the Stabilities and Structures of X-(C6H6) Clusters (X = Cl, Br, and I), Chem. Phys. Lett., 1988, 147, 2-3, 174, https://doi.org/10.1016/0009-2614(88)85078-4 . [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]

Staley and Beauchamp, 1975
Staley, R.H.; Beauchamp, J.L., Intrinsic Acid - Base Properties of Molecules. Binding Energies of Li+ to pi - and n - Donor Bases, J. Am. Chem. Soc., 1975, 97, 20, 5920, https://doi.org/10.1021/ja00853a050 . [all data]

Dzidic and Kebarle, 1970
Dzidic, I.; Kebarle, P., Hydration of the Alkali Ions in the Gas Phase. Enthalpies and Entropies of Reactions M+(H2O)n-1 + H2O = M+(H2O)n, J. Phys. Chem., 1970, 74, 7, 1466, https://doi.org/10.1021/j100702a013 . [all data]

Davidson and Kebarle, 1976
Davidson, W.R.; Kebarle, P., Binding Energies and Stabilities of Potassium Ion Complexes from Studies of Gas Phase Ion Equilibria K+ + M = K+.M, J. Am. Chem. Soc., 1976, 98, 20, 6133, https://doi.org/10.1021/ja00436a011 . [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]

Shaofeng and Pilcher, 1988
Shaofeng, L.; Pilcher, G., Enthalpy of formation of pyridine-N-oxide: the dissociation enthalpy of the (N-O) bond, J. Chem. Thermodyn., 1988, 20, 463-465. [all data]

Rodgers, Stanley, et al., 2000
Rodgers, M.T.; Stanley, J.R.; Amunugama, R., Periodic Trends in the Binding of Metal Ions to Pyridine Studied by Threshold Collision-Induced Dissociation and Density Functional Theory, J. Am. Chem. Soc., 2000, 122, 44, 10969, https://doi.org/10.1021/ja0027923 . [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]

Wind, Papp, et al., 2005
Wind, J.J.; Papp, L.; Happel, M.; Hahn, K.; Andriole, E.J.; Poutsma, J.C., Proton Affinity of beta-Oxalylaminoalanine (BOAA): Incorporation of Direct Entropy Correction into the Single-Reference Kinetic Method, J. Am. Soc. Mass Spectrom., 2005, 16, 1151. [all data]

Arimura and Yoshikawa, 1984
Arimura, M.; Yoshikawa, Y., Ionization efficiency and ionization energy of cyclic compounds by electron impact, Mass Spectrosc. (Tokyo), 1984, 32, 375. [all data]

Lifshitz, 1982
Lifshitz, C., Time-dependent mass spectra and breakdown graphs. 2. The kinetic shift in pyridine, J. Phys. Chem., 1982, 86, 606. [all data]

Kimura, Katsumata, et al., 1981
Kimura, K.; Katsumata, S.; Achiba, Y.; Yamazaki, T.; Iwata, S., Ionization energies, Ab initio assignments, and valence electronic structure for 200 molecules in Handbook of HeI Photoelectron Spectra of Fundamental Organic Compounds, Japan Scientific Soc. Press, Tokyo, 1981. [all data]

Utsunomiya, Kobayashi, et al., 1978
Utsunomiya, C.; Kobayashi, T.; Nagakura, S., Photoelectron angular distribution measurements for some pyridines, Bull. Chem. Soc. Jpn., 1978, 451, 3482. [all data]

Eland, Berkowitz, et al., 1978
Eland, J.H.D.; Berkowitz, J.; Schulte, H.; Frey, R., Rates of unimolecular pyridine ion decay and the heat of formation of C₄H₄⁺, Int. J. Mass Spectrom. Ion Phys., 1978, 28, 297. [all data]

Zaretskii, Oren, et al., 1976
Zaretskii, Z.V.I.; Oren, D.; Kelner, L., Automatic method for the measurement of the electron impact ionization and appearance potentials, Appl. Spectrosc., 1976, 30, 366. [all data]

Van Veen and Plantenga, 1975
Van Veen, E.H.; Plantenga, F.L., Threshold electron-impact excitation spectrum of pyridine, Chem. Phys. Lett., 1975, 30, 28. [all data]

Stefanovic and Grutzmacher, 1974
Stefanovic, D.; Grutzmacher, H.F., The ionisation potential of some substituted pyridines, Org. Mass Spectrom., 1974, 9, 1052. [all data]

King, Murrell, et al., 1972
King, G.H.; Murrell, J.N.; Suffolk, R.J., The vacuum-ultraviolet photoelectron spectra of fluoropyridines, J. Chem. Soc. Dalton Trans., 1972, 564. [all data]

Johnstone and Mellon, 1972
Johnstone, R.A.W.; Mellon, F.A., Electron-impact ionization and appearance potentials, J. Chem. Soc. Faraday Trans. 2, 1972, 68, 1209. [all data]

Distefano, Foffani, et al., 1971
Distefano, G.; Foffani, A.; Innorta, G.; Pignataro, S., Mass spectrometric study of transition metal complexes with ligands having nitrogen or sulphur as donor atom, Adv. Mass Spectrom., 1971, 5, 696. [all data]

Distefano, Foffani, et al., 1971, 2
Distefano, G.; Foffani, A.; Innorta, G.; Pignataro, S., Electron impact ionization potentials of some manganese, chromium and tungsten organometallic derivatives, Int. J. Mass Spectrom. Ion Phys., 1971, 7, 383. [all data]

Potapov and Sorokin, 1970
Potapov, V.K.; Sorokin, V.V., Investigation of ionic molecular reactions proceeding during photoionization of aromatic compounds and alcohols, Dokl. Akad. Nauk SSSR, 1970, 195, 616, In original 848. [all data]

Goffart, Momigny, et al., 1969
Goffart, C.; Momigny, J.; Natalis, P., Photoionization studies by total ionization measurements and photoelectron spectra. II.Pyridine, Intern. J. Mass Spectrom. lon Phys., 1969, 3, 371. [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]

Al-Joboury and Turner, 1964
Al-Joboury, M.I.; Turner, D.W., Molecular photoelectron spectroscopy. Part II. A summary of ionization potentials, J. Chem. Soc., 1964, 4434. [all data]

Akopyan and Vilesov, 1964
Akopyan, M.E.; Vilesov, F.I., Excited states of positive ions and dissociative photoionization of aromatic amines, Dokl. Akad. Nauk SSSR, 1964, 158, 1386, In original 965. [all data]

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Terenin, A., Charge transfer in organic solids, induced by light, Proc. Chem. Soc., London, 1961, 321. [all data]

El-Sayed, Kaaba, et al., 1961
El-Sayed, M.F.A.; Kaaba, M.; Tanaka, Y., Ionization potentials of benzene, hexadeuterobenzene, and pyridine from their observed Rydberg series in the region 600-2000 A, J. Chem. Phys., 1961, 34, 334. [all data]

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Watanabe, K., Ionization potentials of some molecules, J. Chem. Phys., 1957, 26, 542. [all data]

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Hustrulid, A.; Kusch, P.; Tate, J.T., The dissociation of benzene (C₆H₆), pyridine (C₅H₅N) and cyclohexane (C₆H₁₂) by electron impact, Phys. Rev., 1938, 54, 1037. [all data]

Klasinc, Novak, et al., 1978
Klasinc, L.; Novak, I.; Scholz, M.; Kluge, G., Photoelektronenspektren substituierter Pyridine und Benzole und ihre Interpretation durch die CNDO/SWW-Methode, Croat. Chem. Acta, 1978, 51, 43. [all data]

Kobayashi and Nagakura, 1974
Kobayashi, T.; Nagakura, S., Photoelectron spectra of aminopyridines and cyanopyridines, J. Electron Spectrosc. Relat. Phenom., 1974, 4, 207. [all data]

Batich, Heilbronner, et al., 1973
Batich, C.; Heilbronner, E.; Hornung, V.; Ashe, A.J.; Clark, D.T.; Cobley, U.T.; Kilcast, D.; Scanlan, I., Photoelectron spectra of phosphabenzen, arsabenzene, and stibabenzene, J. Am. Chem. Soc., 1973, 95, 928. [all data]

Heilbronner, Hornung, et al., 1972
Heilbronner, E.; Hornung, V.; Pinkerton, F.H.; Thames, S.F., 31. Photoelectron spectra of azabenzenes and azanaphthalenes: III. The orbital sequence in methyl- and trimethylsilyl- substituted pyridines, Helv. Chim. Acta, 1972, 55, 289. [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]

Lifshitz and Malinovich, 1984
Lifshitz, C.; Malinovich, Y., Time resolved photoionization mass spectrometry in the millisecond range, Int. J. Mass Spectrom. Ion Processes, 1984, 60, 99. [all data]

Burgers and Holmes, 1984
Burgers, P.C.; Holmes, J.L., Fragmentation rate constants and appearance energies for reactions having a large kinetic shift and the energy partitioning in their metastable decomposition, Int. J. Mass Spectrom. Ion Processes, 1984, 58, 15. [all data]

Rosenstock, Stockbauer, et al., 1981
Rosenstock, H.M.; Stockbauer, R.; Parr, A.C., Unimolecular kinetis of pyridine ion fragmentation, Int. J. Mass Spectrom. Ion Phys., 1981, 38, 323. [all data]

Rosenstock, McCulloh, et al., 1977
Rosenstock, H.M.; McCulloh, K.E.; Lossing, F.P., On the mechanisms of C₆H₆ ionization fragmentation, Int. J. Mass Spectrom. Ion Phys., 1977, 25, 327. [all data]

Beynon, Hopkinson, et al., 1969
Beynon, J.H.; Hopkinson, J.A.; Lester, G.R., Mass spectrometry-the appearance potentials of "meta-stable peaks" in some aromatic nitro compounds - a chemical reaction in the mass spectrometer, Intern. J. Mass Spectrom. Ion Phys., 1969, 2, 291. [all data]

Notes

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

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  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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