1H-Benzimidazole

• Formula: C₇H₆N₂
• Molecular weight: 118.1359
• IUPAC Standard InChI: InChI=1S/C7H6N2/c1-2-4-7-6(3-1)8-5-9-7/h1-5H,(H,8,9) Copy

  
• IUPAC Standard InChIKey: HYZJCKYKOHLVJF-UHFFFAOYSA-N Copy
• CAS Registry Number: 51-17-2
• Chemical structure:
  This structure is also available as a 2d Mol file or as a computed 3d SD file
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• Other names: Benzimidazole; o-Benzimidazole; Azindole; Benziminazole; Benzoglyoxaline; Benzoimidazole; BZI; N,N'-Methenyl-o-phenylenediamine; 1,3-Benzodiazole; 1,3-Diazaindene; 3-Azaindole; NSC 759
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• Information on this page:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Gas phase ion energetics data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • References
  • Notes
• Other data available:
  • Gas Chromatography
• Data at other public NIST sites:
  • X-ray Photoelectron Spectroscopy Database, version 5.0
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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 by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

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 solid

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:
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.

Enthalpy of sublimation

Enthalpy of fusion

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

Data compiled as indicated in comments:
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi

Ionization energy determinations

IR Spectrum

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Data compiled by: Coblentz Society, Inc.

• SOLID (MINERAL OIL MULL); Not specified, most likely a grating or hybrid spectrometer.; DIGITIZED BY NIST FROM HARD COPY (FROM TWO SEGMENTS); 4 cm^-1 resolution

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

• gas; HP-GC/MS/IRD

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

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Jimenez, Roux, et al., 1987
Jimenez, P.; Roux, M.V.; Turrion, C., Thermochemical properties of N-heterocyclic compounds. I. Enthalpies of combustion, vapour pressures and enthalpies of sublimation, and enthalpies of formation of pyrazole, imidazole, indazole, and benzimidazole, J. Chem. Thermodyn., 1987, 19, 985-992. [all data]

Jimenez, Roux, et al., 1986
Jimenez, P.; Roux, M.V.; Turrion, C.; Gomis, F., Thermochemical properties of some N-heterocyclic compounds, J. Calorim. Anal. Therm. Thermodyn. Chim., 1986, 17, 469-470. [all data]

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

Lehman, Gentry, et al., 1998
Lehman, Richard L.; Gentry, Jefffery S.; Glumac, Nick G., Thermal stability of potassium carbonate near its melting point, Thermochimica Acta, 1998, 316, 1, 1-9, https://doi.org/10.1016/S0040-6031(98)00289-5 . [all data]

Domanska, Kozlowska, et al., 2002
Domanska, Urszula; Kozlowska, Marta Karolina; Rogalski, Marek, Solubilities, Partition Coefficients, Density, and Surface Tension for Imidazoles + Octan-1-ol or + Water or + n -Decane ^«8224», J. Chem. Eng. Data, 2002, 47, 3, 456-466, https://doi.org/10.1021/je0103014 . [all data]

Pitzer, Peiper, et al., 1984
Pitzer, Kenneth S.; Peiper, J. Christopher; Busey, R.H., Thermodynamic Properties of Aqueous Sodium Chloride Solutions, J. Phys. Chem. Ref. Data, 1984, 13, 1, 1, https://doi.org/10.1063/1.555709 . [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]

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]

Ramsey, 1979
Ramsey, B.G., Substituent effects on imidazole basicity and photoelectron spectroscopy determined ionization energies, J. Org. Chem., 1979, 44, 2093. [all data]

Steck, Nachod, et al., 1948
Steck, E.A.; Nachod, F.C.; Ewing, G.W.; Gorman, N.H., Absorption spectra of heterocyclic compounds. III. Some benzimidazole derivatives, J. Am. Chem. Soc., 1948, 70, 3406-3410. [all data]

Notes

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• Symbols used in this document:
  

  Cp,solid	Constant pressure heat capacity of solid
  ΔcH°solid	Enthalpy of combustion of solid at standard conditions
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔfH°solid	Enthalpy of formation of solid at standard conditions
  ΔfusH	Enthalpy of fusion
  ΔsubH	Enthalpy of sublimation
  ΔsubH°	Enthalpy of sublimation at standard conditions

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