Benzene, 1,4-difluoro-

• Formula: C₆H₄F₂
• Molecular weight: 114.0928
• IUPAC Standard InChI: InChI=1S/C6H4F2/c7-5-1-2-6(8)4-3-5/h1-4H Copy

  
• IUPAC Standard InChIKey: QUGUFLJIAFISSW-UHFFFAOYSA-N Copy
• CAS Registry Number: 540-36-3
• 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: Benzene, p-difluoro-; p-Difluorobenzene; 1,4-Difluorobenzene; para-Difluorobenzene
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Gas phase ion energetics data
  • Ion clustering data
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Henry's Law data
  • IR Spectrum
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

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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

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
LL - Sharon G. Lias and Joel F. Liebman
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

C₆H₃F₂^- +  =

By formula: C₆H₃F₂^- + H⁺ = C₆H₄F₂

Ion clustering 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:
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
B - John E. Bartmess
RCD - Robert C. Dunbar

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

C₆H₄F₂⁺ +  = (C₆H₄F₂⁺ • )

By formula: C₆H₄F₂⁺ + C₆H₄F₂ = (C₆H₄F₂⁺ • C₆H₄F₂)

Bond type: Charge transfer bond (positive ion)

C₆H₆⁺ +  = (C₆H₆⁺ • )

By formula: C₆H₆⁺ + C₆H₄F₂ = (C₆H₆⁺ • C₆H₄F₂)

Bond type: Charge transfer bond (positive ion)

 +  = ( • )

By formula: Cl^- + C₆H₄F₂ = (Cl^- • C₆H₄F₂)

 +  = ( • )

By formula: Cr⁺ + C₆H₄F₂ = (Cr⁺ • C₆H₄F₂)

 +  = ( • )

By formula: H₄N⁺ + C₆H₄F₂ = (H₄N⁺ • C₆H₄F₂)

Free energy of reaction

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

References

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), Notes

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

Good, Lacina, et al., 1962
Good, W.D.; Lacina, J.L.; Scott, D.W.; McCullough, J.P., Combustion calorimetry of organic fluorine compounds. The heats of combustion and formation of the difluorobenzenes, 4-fluorotoluene and m-trifluorotoluic acid, J. Phys. Chem., 1962, 66, 1529-1532. [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]

Rieger, Reiser, et al., 1992
Rieger, D.; Reiser, G.; Muller-Dethlefs, K.; Schlag, E.W., Zero kinetic energy photoelectron spectroscopy of p-difluorobenzene, J. Phys. Chem., 1992, 96, 12. [all data]

Reiger, 1990
Reiger, D., [Title unavailable], Diplomarbeit, Techn. Universitat Munich, 1990. [all data]

Bieri, Asbrink, et al., 1981
Bieri, G.; Asbrink, L.; Von Niessen, W., 30.4 nm He(II) photoelectron spectra of organic molecules. Part IV. Fluoro-compounds (C,H,F), J. Electron Spectrosc. Relat. Phenom., 1981, 23, 281. [all data]

Lias and Ausloos, 1978
Lias, S.G.; Ausloos, P.J., eIonization energies of organic compounds by equilibrium measurements, J. Am. Chem. Soc., 1978, 100, 6027. [all data]

Gilbert and Sandorfy, 1974
Gilbert, R.; Sandorfy, C., Rydberg transitions in the ultraviolet spectra of difluorobenzenes, Chem. Phys. Lett., 1974, 27, 457. [all data]

Clark and Frost, 1967
Clark, I.D.; Frost, D.C., A study of the energy levels in benzene and some fluorobenzenes by photoelectron spectroscopy, J. Am. Chem. Soc., 1967, 89, 244. [all data]

Bralsford, Harris, et al., 1960
Bralsford, R.; Harris, P.V.; Price, W.C., The effect of fluorine on the electronic spectra and ionization potentials of molecules, Proc. Roy. Soc. (London), 1960, A258, 459. [all data]

Sell, Mintz, et al., 1978
Sell, J.A.; Mintz, D.M.; Kupperman, A., Photoelectron angular distributions of carbon-carbon π electrons in ethylene, benzene, and their fluorinated derivatives, Chem. Phys. Lett., 1978, 58, 601. [all data]

Streets and Ceasar, 1973
Streets, D.G.; Ceasar, G.P., Inductive mesomeric effects on the π orbitals of halobenzenes, Mol. Phys., 1973, 26, 1037. [all data]

Klessinger, 1972
Klessinger, M., Ionization potentials of substituted benzenes, Angew. Chem. Int. Ed. Engl., 1972, 11, 525. [all data]

Momigny and Wirtz-Cordier, 1962
Momigny, J.; Wirtz-Cordier, A.M., Les effets de l'impact electronique sur des derives dihalogenes du benzene, Ann. Soc. Sci. Bruxelles, 1962, 76, 164. [all data]

Majer and Patrick, 1962
Majer, J.R.; Patrick, C.R., Electron impact on some halogenated aromatic compounds, J. Chem. Soc. Faraday Trans., 1962, 58, 17. [all data]

Buker, Nibbering, et al., 1997
Buker, H.H.; Nibbering, N.M.M.; Espinosa, D.; Mongin, F.; Schlosser, M., Additivity of substituent effects in the fluoroarene series: Equilibrium acidity in the gas phase and deprotonation rates in ethereal solution, Tetrahed. Lett., 1997, 38, 49, 8519-8522, https://doi.org/10.1016/S0040-4039(97)10303-3 . [all data]

Briscese and Riveros, 1975
Briscese, S.M.J.; Riveros, J.M., Gas phase nucleophilic reactions of aromatic systems, J. Am. Chem. Soc., 1975, 97, 230. [all data]

Ernstberger, Krause, et al., 1990
Ernstberger, B.; Krause, H.; Kiermeier, A.; Neusser, H.J., Multiphoton ionization and dissociation of mixed van der Waals clusters in a linear reflectron time-of-flight mass spectrometer, J. Chem. Phys., 1990, 92, 9, 5285, https://doi.org/10.1063/1.458603 . [all data]

Larson and McMahon, 1984
Larson, J.W.; McMahon, T.B., Hydrogen bonding in gas phase anions. An experimental investigation of the interaction between chloride ion and bronsted acids from ICR chloride exchange equilibria, J. Am. Chem. Soc., 1984, 106, 517. [all data]

Larson and McMahon, 1984, 2
Larson, J.W.; McMahon, T.B., Gas phase negative ion chemistry of alkylchloroformates, Can. J. Chem., 1984, 62, 675. [all data]

Ryzhov, 1999
Ryzhov, V., Binding Energies of Chromium Cations with Fluorobenzenes from Radiative Association Kinetics, Int. J. Mass Spectrom., 1999, 185/186/187, 913. [all data]

Deakyne and Meot-Ner (Mautner), 1985
Deakyne, C.A.; Meot-Ner (Mautner), M., Unconventional Ionic Hydrogen Bonds. 2. NH+ pi. Complexes of Onium Ions with Olefins and Benzene Derivatives, J. Am. Chem. Soc., 1985, 107, 2, 474, https://doi.org/10.1021/ja00288a034 . [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, Ion clustering data, Mass spectrum (electron ionization), References

• Symbols used in this document:
  

  AE	Appearance energy
  IE (evaluated)	Recommended ionization energy
  T	Temperature
  ΔfH°gas	Enthalpy of formation of gas 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

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