Difluoromethane

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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 as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity Value Units Method Reference Comment
Δfgas-107.71kcal/molReviewChase, 1998Data last reviewed in December, 1969
Δfgas-108.08 ± 0.22kcal/molCcrNeugebauer and Margrave, 1958Corrected for CODATA value of ΔfH; ALS
Quantity Value Units Method Reference Comment
Δcgas-139.36kcal/molCcrNeugebauer and Margrave, 1958Corrected for CODATA value of ΔfH; ALS
Quantity Value Units Method Reference Comment
gas,1 bar58.963cal/mol*KReviewChase, 1998Data last reviewed in December, 1969

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 (cal/mol*K)
    H° = standard enthalpy (kcal/mol)
    S° = standard entropy (cal/mol*K)
    t = temperature (K) / 1000.

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Temperature (K) 298. to 1200.1200. to 6000.
A -1.45762022.62800
B 42.834611.669091
C -29.24670-0.320721
D 7.7203810.021364
E 0.117438-4.318980
F -108.5430-124.1750
G 46.3188173.39250
H -107.7100-107.7100
ReferenceChase, 1998Chase, 1998
Comment Data last reviewed in December, 1969 Data last reviewed in December, 1969

Reaction 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:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
MS - José A. Martinho Simões
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

CHF2- + Hydrogen cation = Difluoromethane

By formula: CHF2- + H+ = CH2F2

Quantity Value Units Method Reference Comment
Δr389.0 ± 3.5kcal/molCIDTGraul and Squires, 1990gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B
Quantity Value Units Method Reference Comment
Δr381.2 ± 3.6kcal/molH-TSGraul and Squires, 1990gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B
Δr379.0 ± 6.0kcal/molIMRBSullivan, 1977gas phase; B

Lithium ion (1+) + Difluoromethane = (Lithium ion (1+) • Difluoromethane)

By formula: Li+ + CH2F2 = (Li+ • CH2F2)

Quantity Value Units Method Reference Comment
Δr26.5kcal/molICRStaley and Beauchamp, 1975gas phase; switching reaction(Li+)H2O, from graph; Dzidic and Kebarle, 1970 interpolated; M

C5O5W (g) + Difluoromethane (g) = C6H2F2O5W (g)

By formula: C5O5W (g) + CH2F2 (g) = C6H2F2O5W (g)

Quantity Value Units Method Reference Comment
Δr>-5.00kcal/molEqGBrown, Ishikawa, et al., 1990Temperature range: ca. 300-350 K; MS

Difluoromethane + Bromine = Hydrogen bromide + Methane, bromodifluoro-

By formula: CH2F2 + Br2 = HBr + CHBrF2

Quantity Value Units Method Reference Comment
Δr-9.54 ± 0.07kcal/molEqkOkafo and Whittle, 1974gas phase; ALS

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
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)148.3kcal/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity140.9kcal/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
Δr389.0 ± 3.5kcal/molCIDTGraul and Squires, 1990gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B
Quantity Value Units Method Reference Comment
Δr381.2 ± 3.6kcal/molH-TSGraul and Squires, 1990gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B
Δr379.0 ± 6.0kcal/molIMRBSullivan, 1977gas phase; B

Ion clustering data

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

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

Data compiled by: Michael M. Meot-Ner (Mautner) and Sharon G. Lias

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

Lithium ion (1+) + Difluoromethane = (Lithium ion (1+) • Difluoromethane)

By formula: Li+ + CH2F2 = (Li+ • CH2F2)

Quantity Value Units Method Reference Comment
Δr26.5kcal/molICRStaley and Beauchamp, 1975gas phase; switching reaction(Li+)H2O, from graph; Dzidic and Kebarle, 1970 interpolated

Gas Chromatography

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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

Normal alkane RI, non-polar column, temperature ramp

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Column type Active phase I Reference Comment
CapillaryOV-101230.Zenkevich, 200525. m/0.20 mm/0.10 μm, N2/He, 6. K/min; Tstart: 50. C; Tend: 250. C

Normal alkane RI, non-polar column, custom temperature program

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Column type Active phase I Reference Comment
CapillaryPorapack Q183.Zenkevich and Rodin, 2004Program: not specified

References

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Gas Chromatography, 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]

Neugebauer and Margrave, 1958
Neugebauer, C.A.; Margrave, J.L., The heats of formation of CHF3 and CH2F2, J. Phys. Chem., 1958, 62, 1043-1048. [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]

Staley and Beauchamp, 1975
Staley, R.H.; Beauchamp, J.L., Intrinsic Acid - Base Properties of Molecules. Binding Energies of Li+ to pi - and n - Donor Bases, J. Am. Chem. Soc., 1975, 97, 20, 5920, https://doi.org/10.1021/ja00853a050 . [all data]

Dzidic and Kebarle, 1970
Dzidic, I.; Kebarle, P., Hydration of the Alkali Ions in the Gas Phase. Enthalpies and Entropies of Reactions M+(H2O)n-1 + H2O = M+(H2O)n, J. Phys. Chem., 1970, 74, 7, 1466, https://doi.org/10.1021/j100702a013 . [all data]

Brown, Ishikawa, et al., 1990
Brown, C.E.; Ishikawa, Y.; Hackett, P.A.; Rayner, D.M., J. Am. Chem. Soc., 1990, 112, 2530. [all data]

Okafo and Whittle, 1974
Okafo, E.N.; Whittle, E., Bond dissociation energies from equilibrium studies. Part 5.-The equilibria Br2 + CH2F2 = HBr + CHF2Br and Br2 + CH3F = HBr + CH2FBr. Determination of D(CHF2-Br) and ΔH°f (CHF2Br,g), Trans. Faraday Soc., 1974, 17, 1366-1375. [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]

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]

Zenkevich, 2005
Zenkevich, I.G., Experimentally measured retention indices., 2005. [all data]

Zenkevich and Rodin, 2004
Zenkevich, I.G.; Rodin, A.A., Gas chromatographic identification of some volatile toxic fluorine containing compounds by precalculated retention indices, J. Ecol. Chem. (Rus.), 2004, 13, 1, 22-28. [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, Gas Chromatography, References