Difluoromethane
- Formula: CH2F2
- Molecular weight: 52.0234
- IUPAC Standard InChIKey: RWRIWBAIICGTTQ-UHFFFAOYSA-N
- CAS Registry Number: 75-10-5
- 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: Freon 32; Methane, difluoro-; Methylene fluoride; Carbon fluoride hydride; Genetron 32; Methylene difluoride; CH2F2; R 32; HFC 32; R 32 (refrigerant)
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Gas phase thermochemistry data
Go To: Top, Reaction thermochemistry data, 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 |
---|---|---|---|---|---|
ΔfH°gas | -450.66 | kJ/mol | Review | Chase, 1998 | Data last reviewed in December, 1969 |
ΔfH°gas | -452.21 ± 0.92 | kJ/mol | Ccr | Neugebauer and Margrave, 1958 | Corrected for CODATA value of ΔfH; ALS |
Quantity | Value | Units | Method | Reference | Comment |
ΔcH°gas | -583.08 | kJ/mol | Ccr | Neugebauer and Margrave, 1958 | Corrected for CODATA value of ΔfH; ALS |
Quantity | Value | Units | Method | Reference | Comment |
S°gas,1 bar | 246.70 | J/mol*K | Review | Chase, 1998 | Data 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 (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.
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Temperature (K) | 298. to 1200. | 1200. to 6000. |
---|---|---|
A | -6.098682 | 94.67555 |
B | 179.2200 | 6.983473 |
C | -122.3682 | -1.341897 |
D | 32.30207 | 0.089387 |
E | 0.491361 | -18.07061 |
F | -454.1439 | -519.5482 |
G | 193.7979 | 307.0742 |
H | -450.6586 | -450.6586 |
Reference | Chase, 1998 | Chase, 1998 |
Comment | Data last reviewed in December, 1969 | Data last reviewed in December, 1969 |
Reaction thermochemistry data
Go To: Top, Gas phase thermochemistry data, 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:
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- + =
By formula: CHF2- + H+ = CH2F2
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 1628. ± 15. | kJ/mol | CIDT | Graul and Squires, 1990 | gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 1595. ± 15. | kJ/mol | H-TS | Graul and Squires, 1990 | gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B |
ΔrG° | 1586. ± 25. | kJ/mol | IMRB | Sullivan, 1977 | gas phase; B |
By formula: Li+ + CH2F2 = (Li+ • CH2F2)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 111. | kJ/mol | ICR | Staley and Beauchamp, 1975 | gas phase; switching reaction(Li+)H2O, from graph; Dzidic and Kebarle, 1970 interpolated; M |
C5O5W (g) + (g) = C6H2F2O5W (g)
By formula: C5O5W (g) + CH2F2 (g) = C6H2F2O5W (g)
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | >-20.9 | kJ/mol | EqG | Brown, Ishikawa, et al., 1990 | Temperature range: ca. 300-350 K; MS |
By formula: CH2F2 + Br2 = HBr + CHBrF2
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | -39.9 ± 0.3 | kJ/mol | Eqk | Okafo and Whittle, 1974 | gas phase; ALS |
Gas phase ion energetics data
Go To: Top, Gas phase thermochemistry data, Reaction 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:
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) | 12.71 | eV | N/A | N/A | L |
Quantity | Value | Units | Method | Reference | Comment |
Proton affinity (review) | 620.5 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Quantity | Value | Units | Method | Reference | Comment |
Gas basicity | 589.7 | kJ/mol | N/A | Hunter and Lias, 1998 | HL |
Ionization energy determinations
IE (eV) | Method | Reference | Comment |
---|---|---|---|
12.70 | PE | Pullen, Carlson, et al., 1970 | RDSH |
12.72 | PE | Brundle, Robin, et al., 1970 | RDSH |
13.27 | EI | Harshbarger, Robin, et al., 1973 | Vertical value; LLK |
Appearance energy determinations
Ion | AE (eV) | Other Products | Method | Reference | Comment |
---|---|---|---|---|---|
CF+ | 18.8 | ? | EI | Lifshitz and Long, 1965 | RDSH |
CF2+ | 14.8 ± 0.4 | H2 | EI | Steele, 1964 | RDSH |
CHF+ | 17.7 | ? | EI | Lifshitz and Long, 1965 | RDSH |
CHF2+ | 13.11 | H | EI | Lossing, 1972 | LLK |
CHF2+ | 13.14 ± 0.02 | H | EI | Martin, Lampe, et al., 1966 | RDSH |
CHF2+ | 13.1 | H | EI | Lifshitz and Long, 1965 | RDSH |
CH2F+ | 14.06 | F | EI | Lossing, 1972 | LLK |
CH2F+ | 15.28 | F | EI | Lifshitz and Long, 1965 | RDSH |
De-protonation reactions
CHF2- + =
By formula: CHF2- + H+ = CH2F2
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
ΔrH° | 1628. ± 15. | kJ/mol | CIDT | Graul and Squires, 1990 | gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B |
Quantity | Value | Units | Method | Reference | Comment |
ΔrG° | 1595. ± 15. | kJ/mol | H-TS | Graul and Squires, 1990 | gas phase; G2 calculations( Lee, Dyke, et al., 1998) predict ΔHacid = 399 kcal/mol; B |
ΔrG° | 1586. ± 25. | kJ/mol | IMRB | Sullivan, 1977 | gas phase; B |
References
Go To: Top, Gas phase thermochemistry data, Reaction 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]
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]
Notes
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, References
- Symbols used in this document:
AE Appearance energy IE (evaluated) Recommended ionization energy S°gas,1 bar Entropy of gas at standard conditions (1 bar) ΔcH°gas Enthalpy of combustion of gas at standard conditions 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 - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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