Difluoromethane

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 ion energetics data

Go To: Top, 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
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Quantity Value Units Method Reference Comment
IE (evaluated)12.71eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)620.5kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity589.7kJ/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
12.70PEPullen, Carlson, et al., 1970RDSH
12.72PEBrundle, Robin, et al., 1970RDSH
13.27EIHarshbarger, Robin, et al., 1973Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CF+18.8?EILifshitz and Long, 1965RDSH
CF2+14.8 ± 0.4H2EISteele, 1964RDSH
CHF+17.7?EILifshitz and Long, 1965RDSH
CHF2+13.11HEILossing, 1972LLK
CHF2+13.14 ± 0.02HEIMartin, Lampe, et al., 1966RDSH
CHF2+13.1HEILifshitz and Long, 1965RDSH
CH2F+14.06FEILossing, 1972LLK
CH2F+15.28FEILifshitz and Long, 1965RDSH

De-protonation reactions

CHF2- + Hydrogen cation = Difluoromethane

By formula: CHF2- + H+ = CH2F2

Quantity Value Units Method Reference Comment
Δr1628. ± 15.kJ/molCIDTGraul and Squires, 1990gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B
Quantity Value Units Method Reference Comment
Δr1595. ± 15.kJ/molH-TSGraul and Squires, 1990gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B
Δr1586. ± 25.kJ/molIMRBSullivan, 1977gas phase; B

References

Go To: Top, 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.

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]

Pullen, Carlson, et al., 1970
Pullen, B.P.; Carlson, T.A.; Moddeman, W.E.; Schweitzer, G.K.; Bull, W.E., Photoelectron spectra of methane, silane, germane, methyl fluoride, difluoromethane, and trifluoromethane, J. Chem. Phys., 1970, 53, 768. [all data]

Brundle, Robin, et al., 1970
Brundle, C.R.; Robin, M.B.; Basch, H., Electronic energies and electronic structures of the fluoromethanes, J. Chem. Phys., 1970, 53, 2196. [all data]

Harshbarger, Robin, et al., 1973
Harshbarger, W.R.; Robin, M.B.; Lassettre, E.N., The electron impact spectra of the fluoromethanes, J. Electron Spectrosc. Relat. Phenom., 1973, 1, 319. [all data]

Lifshitz and Long, 1965
Lifshitz, C.; Long, F.A., Appearance potentials and mass spectra of fluorinated ethylenes. II. Heats offormation of fluorinated species and their positive ions, J. Phys. Chem., 1965, 69, 3731. [all data]

Steele, 1964
Steele, W.C., Appearance potentials of the difluoromethylene positive ion, J. Phys. Chem., 1964, 68, 2359. [all data]

Lossing, 1972
Lossing, F.P., Free radicals by mass spectrometry. XLIV. Ionization potentials bond dissociation energies for chloro-and fluoromethyl radicals, Bull. Soc. Chim. Belg., 1972, 81, 125. [all data]

Martin, Lampe, et al., 1966
Martin, R.H.; Lampe, F.W.; Taft, R.W., An electron-impact study of ionization and dissociation in methoxy- and halogen- substituted methanes, J. Am. Chem. Soc., 1966, 88, 1353. [all data]

Graul and Squires, 1990
Graul, S.T.; Squires, R.R., Gas-Phase Acidities Derived from Threshold Energies for Activated Reactions, J. Am. Chem. Soc., 1990, 112, 7, 2517, https://doi.org/10.1021/ja00163a007 . [all data]

Lee, Dyke, et al., 1998
Lee, E.P.F.; Dyke, J.M.; Mayhew, C.A., Study of the OH-+CH2F2 reaction by selected ion flow tube experiments and ab initio calculations, J. Phys. Chem. A, 1998, 102, 43, 8349-8354, https://doi.org/10.1021/jp982224y . [all data]

Sullivan, 1977
Sullivan, S.A., Thesis, Cal. Inst. Tech. thesis,, 1977. [all data]


Notes

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