Difluoromethane

• Formula: CH₂F₂
• Molecular weight: 52.0234
• IUPAC Standard InChI: InChI=1S/CH2F2/c2-1-3/h1H2 Copy

  
• IUPAC Standard InChIKey: RWRIWBAIICGTTQ-UHFFFAOYSA-N Copy
• 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)
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Henry's Law data
  • References
  • Notes
• Other data available:
  • Gas phase ion energetics data
  • Ion clustering data
  • Mass spectrum (electron ionization)
  • Gas Chromatography
  • Fluid Properties
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
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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

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

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View table.

Phase change 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:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos

Enthalpy of vaporization

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (atm)
    T = temperature (K)

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Enthalpy of fusion

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^- +  =

By formula: CHF₂^- + H⁺ = CH₂F₂

 +  = ( • )

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

C₅O₅W (g) +  (g) = C₆H₂F₂O₅W (g)

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

 +  =  + 

By formula: CH₂F₂ + Br₂ = HBr + CHBrF₂

Henry's Law 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 by: Rolf Sander

Henry's Law constant (water solution)

k_H(T) = k°_H exp(d(ln(k_H))/d(1/T) ((1/T) - 1/(298.15 K)))
k°_H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(k_H))/d(1/T) = Temperature dependence constant (K)

References

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Henry's Law 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]

PCR Inc., 1990
PCR Inc., Research Chemicals Catalog 1990-1991, PCR Inc., Gainesville, FL, 1990, 1. [all data]

Filatov, Makarov, et al., 1968
Filatov, A.S.; Makarov, S.P.; Yakubovich, A.Ya., Halogenation of 1,1,1-Trifluoroazomethane, Zh. Obshch. Khim., 1968, 38, 33. [all data]

Croll and Scott, 1964
Croll, I.M.; Scott, R.L., Fluorocarbon Solutions at Low Termperatures IV. The Liquid Mixtures CH4 + CClF3, CH2F2 + CClF3, CHF3 + CClF3, CF4 + CClF3, C2H6 + CClF3, C2H6 + CF4, and CHF3 + CF4, J. Phys. Chem., 1964, 68, 3853. [all data]

Henne, Renoll, et al., 1939
Henne, A.L.; Renoll, M.W.; Leicester, H.M., J. Am. Chem. Soc., 1939, 61, 938. [all data]

Shi, Zhu, et al., 1998
Shi, L.; Zhu, M.; Han, L.; Duan, Y.; Sun, L.; Fu, Y.-D., Thermophysical Properties of Difluoromethane (HFC-32), Science in China, Ser. E, 1998, 41, 435-42. [all data]

Fu, Han, et al., 1995
Fu, Y.D.; Han, L.-Z.; Zhu, M.-S., PVT properties, vapor pressures and critical parameters of HFC-32, Fluid Phase Equilib., 1995, 111, 273-86. [all data]

Higashi, 1994
Higashi, Y., Critical parameters for HFC134a, HFC32 and HFC125, Int. J. Refrig., 1994, 17, 524-531. [all data]

Sato, Sato, et al., 1994
Sato, T.; Sato, H.; Watanabe, K., PVT Property Measurements for Difluoromethane, J. Chem. Eng. Data, 1994, 39, 851-4. [all data]

Kanungo, Oi, et al., 1987
Kanungo, Arundhati.; Oi, Takao.; Popowicz, Anthony.; Ishida, Takanobu., Vapor pressure isotope effects in liquid methylene difluoride, J. Phys. Chem., 1987, 91, 15, 4198-4203, https://doi.org/10.1021/j100299a049 . [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Malbrunot, Meunier, et al., 1968
Malbrunot, P.F.; Meunier, P.A.; Scatena, Georges M.; Mears, Whitney H.; Murphy, Kevin Paul.; Sinka, Joseph V., Pressure-volume-temperature behavior of difluoromethane, J. Chem. Eng. Data, 1968, 13, 1, 16-21, https://doi.org/10.1021/je60036a006 . [all data]

L«65533»ddecke and Magee, 1996
L«65533»ddecke, T.O.; Magee, J.W., Molar heat capacity at constant volume of difluoromethane (R32) and pentafluoroethane (R125) from the triple-point temperature to 345 K at pressures to 35 MPa, Int J Thermophys, 1996, 17, 4, 823-849, https://doi.org/10.1007/BF01439192 . [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]

Notes

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Henry's Law data, References

• Symbols used in this document:
  

  Pc	Critical pressure
  S°gas,1 bar	Entropy of gas at standard conditions (1 bar)
  Tboil	Boiling point
  Tc	Critical temperature
  d(ln(kH))/d(1/T)	Temperature dependence parameter for Henry's Law constant
  k°H	Henry's Law constant at 298.15K
  ΔcH°gas	Enthalpy of combustion of gas at standard conditions
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔfusH	Enthalpy of fusion
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔvapH	Enthalpy of vaporization
  ρc	Critical density

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