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
  • Phase change data
  • Reaction thermochemistry data
  • Henry's Law data
  • Gas phase ion energetics data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • References
  • Notes
• Other data available:
  • Ion clustering data
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
  • X-ray Photoelectron Spectroscopy Database, version 5.0
• Options:
  • Switch to SI units

Data at NIST subscription sites:

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

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Gas phase thermochemistry data

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Henry's Law data, Gas phase ion energetics data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, 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

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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 liquid

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:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
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.
DH - Eugene S. Domalski and Elizabeth D. Hearing

Enthalpy of vaporization

Enthalpy of vaporization

Δ_vapH = A exp(-βT_r) (1 − T_r)^β
    Δ_vapH = Enthalpy of vaporization (at saturation pressure) (kcal/mol)
    T_r = reduced temperature (T / T_c)

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Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (atm)
    T = temperature (K)

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Enthalpy of fusion

Entropy of fusion

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
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)

Henry's Law 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: Rolf Sander

Henry's Law constant (water solution)

k_H(T) = k°_H exp(d(ln(k_H))/d(1/T) ((1/T) - 1/(298.15 K)))
k°_H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(k_H))/d(1/T) = Temperature dependence constant (K)

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
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

IR Spectrum

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Data compiled by: Coblentz Society, Inc.

• GAS (15 mmHg, N2 ADDED, TOTAL PRESSURE 600 mmHg); DOW KBr FOREPRISM-GRATING; DIGITIZED BY COBLENTZ SOCIETY (BATCH II) FROM HARD COPY; 2 cm^-1 resolution
• SOLUTION (10% IN CCl4 FOR 3800-1300, 10% IN CS2 FOR 1300-650, 10% IN CCl4 FOR 650-250 CM^-1) VERSUS SOLVENT; PERKIN-ELMER 521 (GRATING); DIGITIZED BY NIST FROM HARD COPY (FROM TWO SEGMENTS); 4 cm^-1 resolution
• VAPOR (0.5 MICROLITER AT 150 C); NICOLET FTIR; DIGITIZED BY NIST FROM HARD COPY (FROM TWO SEGMENTS); 4 CM^-1 cm^-1 resolution

Data compiled by: Tanya L. Myers, Russell G. Tonkyn, Ashley M. Oeck, Tyler O. Danby, John S. Loring, Matthew S. Taubman, Stephen W. Sharpe, Jerome C. Birnbaum, and Timothy J. Johnson

• liquid; Bruker Tensor 27 FTIR; 0.4821395 cm^-1 resolution

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

• gas

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

UV/Visible 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: Victor Talrose, Eugeny B. Stern, Antonina A. Goncharova, Natalia A. Messineva, Natalia V. Trusova, Margarita V. Efimkina

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, Henry's Law data, Gas phase ion energetics data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, 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]

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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]

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Swietoslawski, Tybicka, et al., 1931, 2
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Helm, Lanum, et al., 1958
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McCullough, Douslin, et al., 1957, 2
McCullough, J.P.; Douslin, D.R.; Messerly, J.F.; Hossenlopp, I.A.; Kincheloe, T.C.; Waddington, G., Pyridine: Experimental and Calculated Chemical Thermodynamic Prop- erties Between 0 and 1500 K; A Revised Vibrational Assignment, J. Am. Chem. Soc., 1957, 79, 4289. [all data]

Brunner, 1987
Brunner, E., Fluid mixtures at high pressures VI. Phase separation and critical phenomina in 18 binary mixtures containing either pyridine or ethanoic acid, J. Chem. Thermodyn., 1987, 19, 823. [all data]

Kobe, Ravicz, et al., 1956
Kobe, K.A.; Ravicz, A.E.; Vohra, S.P., Critical Properties and Vapor Pressures of Some Ethers and Heterocyclic Compounds, J. Chem. Eng. Data, 1956, 1, 50. [all data]

Herz and Neukirch, 1923
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Majer and Svoboda, 1985
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Ukraintseva, Soldatov, et al., 1997
Ukraintseva, E.A.; Soldatov, D.V.; Dyadin, Yu.A., Pyridine vapor pressure and thermodynamic parameters of clathrate and complex formation in the pyridine-zinc nitrate system, Zh. Neorg. Khim., 1997, 42, 2, 283. [all data]

Blanco, Beltran, et al., 1994
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Lencka, 1990
Lencka, Malgorzata, Measurements of the vapour pressures of pyridine, 2-methylpyridine, 2,4-dimethylpyridine, 2,6-dimethylpyridine, and 2,4,6-trimethylpyridine from 0.1 kPa to atmospheric pressure using a modified Swietoslawski ebulliometer, The Journal of Chemical Thermodynamics, 1990, 22, 5, 473-480, https://doi.org/10.1016/0021-9614(90)90139-H . [all data]

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Majer, Svoboda, et al., 1984
Majer, V.; Svoboda, V.; Lencka, M., Enthalpies of vaporization and cohesive energies of pyridine and isomeric methylpyridines, J. Chem. Thermodyn., 1984, 16, 1019-1024. [all data]

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Herington, E.F.G.; Martin, J.F., Vapour pressures of pyridine and its homologues, Trans. Faraday Soc., 1953, 49, 154, https://doi.org/10.1039/tf9534900154 . [all data]

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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]

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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]

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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]

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Burrows and King, 1935
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Hiraoka, Mizuse, et al., 1988
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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
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Notes

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• Symbols used in this document:
  

  AE	Appearance energy
  Cp,liquid	Constant pressure heat capacity of liquid
  IE (evaluated)	Recommended ionization energy
  Pc	Critical pressure
  S°liquid	Entropy of liquid at standard conditions
  Tboil	Boiling point
  Tc	Critical temperature
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  Vc	Critical volume
  d(ln(kH))/d(1/T)	Temperature dependence parameter for Henry's Law constant
  k°H	Henry's Law constant at 298.15K
  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
  ΔfusS	Entropy of fusion
  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
  ΔvapH°	Enthalpy of vaporization at standard conditions

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