Methylene, difluoro-

• Formula: CF₂
• Molecular weight: 50.0075
• IUPAC Standard InChI: InChI=1S/CF2/c2-1-3 Copy

  
• IUPAC Standard InChIKey: LTVOKYUPTHZZQH-UHFFFAOYSA-N Copy
• CAS Registry Number: 2154-59-8
• 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: Calcium difluoride; Difluoromethylene
• 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
  • References
  • Notes
• Other data available:
  • Reaction thermochemistry data
  • Ion clustering data
  • Vibrational and/or electronic energy levels
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Electron-Impact Ionization Cross Sections (on physics web site)
  • Gas Phase Kinetics Database
  • X-ray Photoelectron Spectroscopy Database, version 5.0
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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, 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

Gas Phase Heat Capacity (Shomate Equation)

C_p° = A + B*t + C*t² + D*t³ + E/t²
H° − H°_298.15= A*t + B*t²/2 + C*t³/3 + D*t⁴/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t²/2 + D*t³/3 − E/(2*t²) + G
    C_p = heat capacity (J/mol*K)
    H° = standard enthalpy (kJ/mol)
    S° = standard entropy (J/mol*K)
    t = temperature (K) / 1000.

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Gas phase ion energetics data

Go To: Top, Gas 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:
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
B - John E. Bartmess

View reactions leading to CF₂⁺ (ion structure unspecified)

Electron affinity determinations

Ionization energy determinations

Appearance energy determinations

References

Go To: Top, Gas 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.

Chase, 1998
Chase, M.W., Jr., NIST-JANAF Themochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]

Ehlert, 1969
Ehlert, T.C., Bonding in C₁ and C₂ fluroides, J. Phys. Chem., 1969, 73, 949-953. [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]

Schwartz, Davico, et al., 1999
Schwartz, R.L.; Davico, G.E.; Ramond, T.M.; Lineberger, W.C., Singlet-triplet splittings in CX2 (X = F, Cl, Br, I) dihalocarbenes via negative ion photoelectron spectroscopy, J. Phys. Chem. A, 1999, 103, 41, 8213-8221, https://doi.org/10.1021/jp992214c . [all data]

Murray, Leopold, et al., 1988
Murray, K.K.; Leopold, D.G.; Miller, T.M.; Lineberger, W.C., Photoelectron Spectroscopy of the Halocarbene Anions HCF^-, HCCl^-, HCBr^-, HCI^-, CF₂^-, and CCl₂^-, J. Chem. Phys., 1988, 89, 9, 5442, https://doi.org/10.1063/1.455596 . [all data]

Born, Ingemann, et al., 1994
Born, M.; Ingemann, S.; Nibbering, N.M.M., Heats of formation of mono-halogen-substituted carbenes. Stability and reactivity of CHX(center dot-) (X=F, Cl, Pr, and I) radical anions, J. Am. Chem. Soc., 1994, 116, 16, 7210, https://doi.org/10.1021/ja00095a025 . [all data]

Harland and Thynne, 1972
Harland, P.W.; Thynne, J.C.J., Ionisation of perfluorocyclobutane by electron impact, Int. J. Mass Spectrom. Ion Phys., 1972, 10, 11. [all data]

Thynne and MacNeil, 1970
Thynne, J.C.J.; MacNeil, K.A.G., Ionisation of Tetrafluoroethylene by Electron Impact, Int. J. Mass Spectrom. Ion Phys., 1970, 5, 3-4, 329, https://doi.org/10.1016/0020-7381(70)80026-2 . [all data]

Page and Goode, 1969
Page, F.M.; Goode, G.C., Negative Ions and the Magnetron., Wiley, NY, 1969. [all data]

Buckley, Johnson, et al., 1995
Buckley, T.J.; Johnson, R.D.; Huie, R.E.; Zhang, Z.; Kuo, S.C.; Klemm, R.B., Ionization energies, appearance energies, and thermochemistry of CF₂O and FCO, J. Phys. Chem., 1995, 99, 4879. [all data]

Goto, Nakamura, et al., 1994
Goto, M.; Nakamura, K.; Toyoda, H.; Sugai, H., Cross section measurements for electron-impact dissociation of CHF₃ into neutral and ionic fragments, Jpn. J. Appl. Phys. Part 1, 1994, 33, 3602. [all data]

Tarnovsky and Becker, 1993
Tarnovsky, V.; Becker, K., Absolute partial cross sections for the parent ionization of the CF_x (x = 1-3) free radicals by electron impact, J. Chem. Phys., 1993, 98, 7868. [all data]

Hildenbrand, 1975
Hildenbrand, D.L., Vertical ionization potential of the CF₂ radical, Chem. Phys. Lett., 1975, 32, 30. [all data]

Dyke, Golob, et al., 1974
Dyke, J.M.; Golob, L.; Jonathan, N.; Morris, A.; Okuda, M., Vacuum ultraviolet photoelectron spectroscopy of transient species. Part 4. Difluoromethylene and ozone, J. Chem. Soc. Faraday Trans. 2, 1974, 70, 1828. [all data]

Reinke, Kraessig, et al., 1973
Reinke, D.; Kraessig, R.; Baumgartel, H., Photoreactions of small organic molecules, Z. Naturforsch. A:, 1973, 28, 1021. [all data]

Hildenbrand, 1973
Hildenbrand, D.L., Mass spectrometric studies of some gaseous sulfur fluorides, J. Phys. Chem., 1973, 77, 897. [all data]

Ehlert, 1969, 2
Ehlert, T.C., Bonding in C₁ and C₂ fluorides, J. Phys. Chem., 1969, 73, 949. [all data]

Zmbov, Uy, et al., 1968
Zmbov, K.F.; Uy, M.; Margrave, J.L., Mass spectrometric study of the high-temperature equilibrium C₂F₄ = 2CF₂ and the heat of formation of the CF₂ radical, J. Am. Chem. Soc., 1968, 90, 5090. [all data]

Pottie, 1965
Pottie, R.F., Ionization potential and heat of formation of the difluoromethylene radical, J. Chem. Phys., 1965, 42, 2607. [all data]

Fisher, Homer, et al., 1965
Fisher, I.P.; Homer, J.B.; Lossing, F.P., Free radicals by mass spectrometry. XXXIII. Ionization potentials of CF₂, CF₃CF₂, CF₃CH₂, n-C₃F₇, and i-C₃F₇ radicals, J. Am. Chem. Soc., 1965, 87, 957. [all data]

Tarnovsky, Kurunczi, et al., 1993
Tarnovsky, V.; Kurunczi, P.; Rogozhnikov, D.; Becker, K., Absolute cross sections for the dissociative electron impact ionization of the CFx (x=1-3) free radicals, Int. J. Mass Spectrom. Ion Processes, 1993, 128, 181. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Gas phase ion energetics data, References

• Symbols used in this document:
  

  AE	Appearance energy
  EA	Electron affinity
  IE (evaluated)	Recommended ionization energy
  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  ΔfH°gas	Enthalpy of formation of gas at standard conditions

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