Difluoromethane
- Formula: CH2F2
- Molecular weight: 52.0234
- IUPAC Standard InChI: InChI=1S/CH2F2/c2-1-3/h1H2
- 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
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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 |
|---|---|---|---|---|---|
| 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 |
Gas Chromatography
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 compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director
Normal alkane RI, non-polar column, temperature ramp
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | OV-101 | 230. | Zenkevich, 2005 | 25. 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
| Column type | Active phase | I | Reference | Comment |
|---|---|---|---|---|
| Capillary | Porapack Q | 183. | Zenkevich and Rodin, 2004 | Program: not specified |
References
Go To: Top, Gas phase thermochemistry 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]
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, Gas Chromatography, References
- Symbols used in this document:
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 - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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