Indole

• Formula: C₈H₇N
• Molecular weight: 117.1479
• IUPAC Standard InChI: InChI=1S/C8H7N/c1-2-4-8-7(3-1)5-6-9-8/h1-6,9H Copy

  
• IUPAC Standard InChIKey: SIKJAQJRHWYJAI-UHFFFAOYSA-N Copy
• CAS Registry Number: 120-72-9
• 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: 1H-Indole; Ketole; 1-Azaindene; 1-Benzazole; 2,3-Benzopyrrole; Benzopyrrole; Indol; 1-H-indol
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • Ion clustering data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • References
  • Notes
• Other data available:
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
• Options:
  • Switch to calorie-based units

Data at NIST subscription sites:

• 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.

Condensed phase thermochemistry data

Go To: Top, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering 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 by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Phase change data

Go To: Top, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering 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:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Reduced pressure boiling point

Enthalpy of sublimation

Reaction thermochemistry data

Go To: Top, Condensed phase thermochemistry data, Phase change data, Gas phase ion energetics data, Ion clustering 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:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias

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

C₈H₆N^- +  =

By formula: C₈H₆N^- + H⁺ = C₈H₇N

 +  = ( • )

By formula: C₂H₃O₂^- + C₈H₇N = (C₂H₃O₂^- • C₈H₇N)

Gas phase ion energetics data

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Ion clustering 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 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
LL - Sharon G. Lias and Joel F. Liebman
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 C₈H₇N⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

De-protonation reactions

C₈H₆N^- +  =

By formula: C₈H₆N^- + H⁺ = C₈H₇N

Ion clustering data

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry 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:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias

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: C₂H₃O₂^- + C₈H₇N = (C₂H₃O₂^- • C₈H₇N)

IR Spectrum

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, 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 by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Gas Phase Spectrum

Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.

For Zoom

1.) Enter the desired X axis range (e.g., 100, 200)

2.) Check here for automatic Y scaling

3.) Press here to zoom

Notice: Concentration information is not available for this spectrum and, therefore, molar absorptivity values cannot be derived.

Additional Data

Mass spectrum (electron ionization)

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, 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 by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.

For Zoom

1.) Enter the desired X axis range (e.g., 100, 200)

2.) Check here for automatic Y scaling

3.) Press here to zoom

Additional Data

UV/Visible spectrum

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, Mass spectrum (electron ionization), References, Notes

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

Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.

For Zoom

1.) Enter the desired X axis range (e.g., 100, 200)

2.) Check here for automatic Y scaling

3.) Press here to zoom

Additional Data

References

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering 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.

Good, 1972
Good, W.D., Enthalpies of combustion of nine organic nitrogen compounds related to petroleum, J. Chem. Eng. Data, 1972, 17, 28-31. [all data]

Zimmerman and Geisenfelder, 1961
Zimmerman, H.; Geisenfelder, H., Uber die Mesomerieenergie von Azolen, Z. Electrochem., 1961, 65, 368-371. [all data]

Stern and Klebs, 1933
Stern, A.; Klebs, G., Calorimetrische Bestimmungen bei einfachen und mehrkernigen Pyrrolderivaten, Ann., 1933, 504, 287-297. [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]

Cooper, Crowne, et al., 1967
Cooper, A.R.; Crowne, C.W.P.; Farrell, P.G., Gas-Liquid Chromatographic Studies of Electron-Donor-Acceptor Systems, Trans. Faraday Soc., 1967, 63, 447. [all data]

Lecat, 1947
Lecat, M., Some azeotropes of which one constituant is heterocyclic nitrogen, Ann. Soc. Sci. Bruxelles, Ser. 1, 1947, 61, 73. [all data]

Adkins and Coonradt, 1941
Adkins, H.; Coonradt, H.L., The Selective Hydrogenation of Derivatives of Pyrrole, Indole, Carbazole and Acridine, J. Am. Chem. Soc., 1941, 63, 1563-70. [all data]

Ribeiro da Silva, Cabral, et al., 2008
Ribeiro da Silva, Manuel A.V.; Cabral, Joana I.T.A.; Gomes, Jose R.B., Experimental and Computational Study on the Molecular Energetics of Indoline and Indole, J. Phys. Chem. A, 2008, 112, 47, 12263-12269, https://doi.org/10.1021/jp8065212 . [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Arshadi, 1974
Arshadi, Mohammed R., Determination of heats of sublimation of organic compounds by a mass spectrometric--knudsen effusion method, J. Chem. Soc., Faraday Trans. 1, 1974, 70, 0, 1569, https://doi.org/10.1039/f19747001569 . [all data]

Aihara, 1955
Aihara, A., J. Chem. Soc. Jpn. Pure Chem. Sect., 1955, 76, 497. [all data]

Serpinskii, Voitkevich, et al., 1954
Serpinskii, V.V.; Voitkevich, S.A.; Lyuboshits, N.Y., Zh. Fiz. Khim., 1954, 28, 810. [all data]

Jones, 1960
Jones, A.H., Sublimation Pressure Data for Organic Compounds., J. Chem. Eng. Data, 1960, 5, 2, 196-200, https://doi.org/10.1021/je60006a019 . [all data]

Meot-ner, Liebman, et al., 1988
Meot-ner, M.; Liebman, J.F.; Kafafi, S.A., Ionic Probes of Aromaticity in Annelated Rings, J. Am. Chem. Soc., 1988, 110, 18, 5937, https://doi.org/10.1021/ja00226a001 . [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]

Taft and Bordwell, 1988
Taft, R.W.; Bordwell, F.G., Structural and Solvent Effects Evaluated from Acidities Measured in Dimethyl Sulfoxide and in the Gas Phase, Acc. Chem. Res., 1988, 21, 12, 463, https://doi.org/10.1021/ar00156a005 . [all data]

Meot-ner, 1988
Meot-ner, M., Ionic Hydrogen Bond and Ion Solvation. ₆. Interaction Energies of the Acetate Ion with Organic Molecules. Comparison of CH₃COO^- with Cl^-, CN^-, and SH^-, J. Am. Chem. Soc., 1988, 110, 12, 3854, https://doi.org/10.1021/ja00220a022 . [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]

Carles, Desfrancois, et al., 2000
Carles, S.; Desfrancois, C.; Schermann, J.P.; Smith, D.M.A.; Adamowicz, L., Structures and electron affinities of indole-(water)(N) clusters, J. Chem. Phys., 2000, 112, 8, 3726-3734, https://doi.org/10.1063/1.480938 . [all data]

Hager and Wallace, 1988
Hager, J.W.; Wallace, S.C., Two-laser photoionization supersonic jet mass spectrometry of aromatic molecules, Anal. Chem., 1988, 60, 5. [all data]

Hager, Ivanco, et al., 1985
Hager, J.; Ivanco, M.; Smith, M.A.; Wallace, S.C., Solvation effects in jet-cooled Van der Waals Clusters: Two-color threshold photoionization spectroscopy of indole, indole-argon, indole-methane, indole-water and indole-methanol, Chem. Phys. Lett., 1985, 113, 503. [all data]

Corval, 1979
Corval, M., Elimination sous impact electronique de HCN et H a partir de l'Indole. Comparaison avec l'Indolizine, Org. Mass Spectrom., 1979, 14, 213. [all data]

Thorstad and Undheim, 1974
Thorstad, O.; Undheim, K., Mass spectrometry of onium compounds. XXIV. Ionisation potential in structure analysis of pyridodiazo-oxides, Chem. Scr., 1974, 6, 222. [all data]

Dewar, Harget, et al., 1970
Dewar, M.J.S.; Harget, A.J.; Trinajstic, N.; Worley, S.D., Ground states of conjugated molecules-XXI.Benzofurans and benzopyrroles, Tetrahedron, 1970, 26, 4505. [all data]

Eland, 1969
Eland, J.H.D., Photoelectron spectra of conjugated hydrocarbons and heteromolecules, Intern. J. Mass Spectrom. Ion Phys., 1969, 2, 471. [all data]

Kovac, Klasinc, et al., 1980
Kovac, B.; Klasinc, L.; Stanovnik, B.; Tisler, M., Photoelectron spectroscopy of J. Heterocycl. Chem.. Azaindenes azaindolizines (1), J. Heterocycl. Chem., 1980, 17, 689. [all data]

Domelsmith, Munchausen, et al., 1977
Domelsmith, L.N.; Munchausen, L.L.; Houk, K.N., Photoelectron spectra of psychotropic drugs. 1. Phenethylamines, tryptamines, and LSD, J. Am. Chem. Soc., 1977, 99, 4311. [all data]

Gusten, Klasinc, et al., 1976
Gusten, H.; Klasinc, L.; Ruscic, B., Photoelectron spectroscopy of J. Heterocycl. Chem.. Indene analogs, Z. Naturforsch. A:, 1976, 31, 1051. [all data]

Dolby, Hanson, et al., 1976
Dolby, L.J.; Hanson, G.; Koenig, T., The He I photoelectron spectra of N-methylisoindole and N-methylindole, J. Org. Chem., 1976, 41, 3537. [all data]

Plieninger, Hobel, et al., 1963
Plieninger, H.; Hobel, M.; Liede, V., Synthese des 4-Dimethylallyl-tryptophans sowie der Tryptophan-essigsaure-(4), Chem. Ber., 1963, 96, 1618-1629. [all data]

Notes

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, Mass spectrum (electron ionization), UV/Visible spectrum, References

• Symbols used in this document:
  

  EA	Electron affinity
  IE (evaluated)	Recommended ionization energy
  Tboil	Boiling point
  Tfus	Fusion (melting) point
  ΔcH°solid	Enthalpy of combustion of solid at standard conditions
  ΔfH°solid	Enthalpy of formation of solid 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
  ΔsubH	Enthalpy of sublimation
  ΔsubH°	Enthalpy of sublimation 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.