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:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Phase change data
  • Reaction thermochemistry 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
• Options:
  • Switch to calorie-based units

Data at NIST subscription sites:

• NIST / TRC Web Thermo Tables, "lite" edition (thermophysical and thermochemical data)
• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.

Gas phase thermochemistry data

Go To: Top, Condensed phase thermochemistry data, 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:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, 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:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Constant pressure heat capacity of liquid

Gas phase ion energetics data

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

Hubbard, Frow, et al., 1961
Hubbard, W.N.; Frow, F.R.; Waddington, G., The heats of combustion and formation of pyridine and hippuric acid, J. Phys. Chem., 1961, 65, 1326-1328. [all data]

Andon, Cox, et al., 1957
Andon, R.J.L.; Cox, J.D.; Herington, E.F.G.; Martin, J.F., The second virial coefficients of pyridine and benzene, and certain of their methyl homologues, Trans. Faraday Soc., 1957, 53, 1074. [all data]

Cox, Challoner, et al., 1954
Cox, J.D.; Challoner, A.R.; Meetham, A.R., The heats of combustion of pyridine and certain of its derivatives, J. Chem. Soc., 1954, 265-271. [all data]

Constam and White, 1903
Constam, E.J.; White, J., Physico-chemical investigations in the pyridine series, Am. Chem. J., 1903, 29, 1-49. [all data]

Strepikheev, Baranov, et al., 1962
Strepikheev, Yu.A.; Baranov, Yu.I.; Burmistrova, O.A., Determination of the heats of combustion and the heat capacities of several mono- and di-isocyanates, Izv. Vyssh. Uchebn. Zaved., Khim. Khim. Tekhnol., 1962, 5, 387-390. [all data]

McCullough, Douslin, et al., 1957
McCullough, J.P.; Douslin, D.R.; Messerly, J.F.; Hossenlopp, I.A.; Kincheloe, T.C.; Waddington, G., Pyridine: experimental and calculated chemical thermodynamic properties between 0 and 1500 K., a revised vibrational assignment, J. Am. Chem. Soc., 1957, 79, 4289-4295. [all data]

Parks, Todd, et al., 1936
Parks, G.S.; Todd, S.S.; Moore, W.A., Thermal data on organic compounds. XVI. Some heat capacity, entropy and free energy data for typical benzene derivatives and heterocyclic compounds, J. Am. Chem. Soc., 1936, 58, 398-401. [all data]

Pearce and Bakke, 1936
Pearce, J.N.; Bakke, H.M., The heat capacity and the free energy of formation of pyridine, Proc. Iowa Acad. Sci., 1936, 43, 171-174. [all data]

Rastorguev and Ganiev, 1967
Rastorguev, Yu.L.; Ganiev, Yu.A., Study of the heat capacity of selected solvents, Izv. Vyssh. Uchebn. Zaved. Neft Gaz. 10, 1967, No.1, 79-82. [all data]

Swietoslawski and Zielenkiewicz, 1958
Swietoslawski, W.; Zielenkiewicz, A., Mean specific heat of some ternary azeotropes, Bull. Acad. Pol. Sci. Ser. Sci. Chim., 1958, 6, 365-366. [all data]

Radulescu and Jula, 1934
Radulescu, D.; Jula, O., Beiträge zur Bestimmung der Abstufung der Polarität des Aminstickstoffes in den organischen Verbindungen, Z. Phys. Chem., 1934, B26, 390-393. [all data]

Swietoslawski, Tybicka, et al., 1931
Swietoslawski, W.; Tybicka, S.; Solodkowska, W., Sur un microcalorimetre adiabatique, adapte aux mesures de la chaleur specifique de substances solides et liquides, Bull. Int. Acad. Pol. Sci. Lett. Cl. Sci. Math Nat. Ser A, 1931, 1931, 322-335. [all data]

Swietoslawski, Tybicka, et al., 1931, 2
Swietoslawski, W.; Tybicka, S.; Solodkowska, W., Sur un microcalorimetre adiabatique, adapte aux mesures de la chaleur specifique de substances solides et liquides, Rocz. Chem., 1931, 11, 65-77. [all data]

Mathews, Krause, et al., 1917
Mathews, J.H.; Krause, E.L.; Bohnson, B.L., a contribution to the thermal chemistry of pyridine, J. Am. Chem. Soc., 1917, 39, 398-413. [all data]

Bramley, 1916
Bramley, A., The study of binary mixtures. Part IV. Heats of reaction and specific heats, J. Chem. Soc. (London), 1916, 109, 496-515. [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]

Terenin, 1961
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]

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

Hustrulid, Kusch, et al., 1938
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]

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]

Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase 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°liquid	Entropy of liquid at standard conditions
  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

• 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.
• Customer support for NIST Standard Reference Data products.