Methylene, difluoro-

Data at NIST subscription sites:

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.


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

Quantity Value Units Method Reference Comment
Δfgas-182.00kJ/molReviewChase, 1998Data last reviewed in June, 1970
Δfgas-172. ± 8.4kJ/molEqkEhlert, 1969ALS
Quantity Value Units Method Reference Comment
gas,1 bar240.83J/mol*KReviewChase, 1998Data last reviewed in June, 1970

Gas Phase Heat Capacity (Shomate Equation)

Cp° = 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
    Cp = heat capacity (J/mol*K)
    H° = standard enthalpy (kJ/mol)
    S° = standard entropy (J/mol*K)
    t = temperature (K) / 1000.

View plot Requires a JavaScript / HTML 5 canvas capable browser.

View table.

Temperature (K) 298. to 600.600. to 6000.
A 8.82577259.34753
B 125.3652-2.317176
C -129.49400.890518
D 50.33101-0.055879
E 0.259749-3.467545
F -188.2917-209.6155
G 220.9081298.2569
H -182.0040-182.0040
ReferenceChase, 1998Chase, 1998
Comment Data last reviewed in June, 1970 Data last reviewed in June, 1970

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)

Quantity Value Units Method Reference Comment
IE (evaluated)11.44 ± 0.03eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)765.kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity732.5kJ/molN/AHunter and Lias, 1998HL

Electron affinity determinations

EA (eV) Method Reference Comment
0.180 ± 0.020LPESSchwartz, Davico, et al., 1999Neutral carbene triplet 54±3 kcal/mol above singlet; B
0.1790 ± 0.0050LPESMurray, Leopold, et al., 1988Singlet-triplet splitting in neutral > 50 kcal/mol; B
0.07 ± 0.15D-EABorn, Ingemann, et al., 1994B
<1.30 ± 0.80EIAEHarland and Thynne, 1972From C2F4. G3MP2B3 calculations indicate an EA of ca. 0.4 eV.; B
>0.20047EIAEThynne and MacNeil, 1970From C2F4. G3MP2B3 calculations indicate an EA of ca. 0.4 eV.; B
2.64955SIPage and Goode, 1969The Magnetron method, lacking mass analysis, is not considered reliable.; B

Ionization energy determinations

IE (eV) Method Reference Comment
11.445 ± 0.025PIBuckley, Johnson, et al., 1995LL
15.2EIGoto, Nakamura, et al., 1994LL
11.5 ± 0.4EITarnovsky and Becker, 1993LL
11.4 ± 0.3EIHildenbrand, 1975LLK
11.5 ± 0.1EIHildenbrand, 1975LLK
11.42 ± 0.01PEDyke, Golob, et al., 1974LLK
9.74DERReinke, Kraessig, et al., 1973LLK
11.54 ± 0.10EIHildenbrand, 1973LLK
11.7 ± 0.2EIEhlert, 1969, 2RDSH
11.8 ± 0.3EIZmbov, Uy, et al., 1968RDSH
11.9 ± 0.1EIPottie, 1965RDSH
11.7 ± 0.1EIFisher, Homer, et al., 1965RDSH

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CF+18.5FEIGoto, Nakamura, et al., 1994LL
CF+14.6 ± 0.4FEITarnovsky, Kurunczi, et al., 1993LL
F+31.4 ± 1.0CF+EITarnovsky, Kurunczi, et al., 1993LL

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 CFx (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