Selected ATcT [1, 2] enthalpy of formation based on version 1.124 of the Thermochemical Network [3]

This version of ATcT results was generated by additional expansion of version 1.122x [4] to include additional information relevant to the study of thermophysical and thermochemical properties of CH2 and CH3 using nonrigid rotor anharmonic oscillator (NRRAO) partition functions [5], the development and benchmarking of a state-of-the-art computational approach that aims to reproduce total atomization energies of small molecules within 10–15 cm^-1 [6], as well as the study of the reversible reaction C₂H₃ + H₂ ⇌ C₂H₄ + H ⇌ C₂H₅ [7]

Difluoromethane

Formula: CH2F2 (l)

CAS RN: 75-10-5

ATcT ID: 75-10-5*590

SMILES: C(F)F

InChI: InChI=1S/CH2F2/c2-1-3/h1H2

InChIKey: RWRIWBAIICGTTQ-UHFFFAOYSA-N

Hills Formula: C1H2F2

2D Image:

Aliases: CH2F2; Difluoromethane; Methylene fluoride; Methylene difluoride; Methane difluoride; Carbon difluoride; Difluorocarbon; FC 32; HFC 32; Freon 32; Genetron 32; R 32

Relative Molecular Mass: 52.02339 ± 0.00081

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
	-468.98	± 0.35	kJ/mol

Top contributors to the provenance of Δ_fH° of CH2F2 (l)

The 20 contributors listed below account only for 66.7% of the provenance of Δ_fH° of CH2F2 (l).
A total of 83 contributors would be needed to account for 90% of the provenance.

Please note: The list is limited to 20 most important contributors or, if less, a number sufficient to account for 90% of the provenance. The Reference acts as a further link to the relevant references and notes for the measurement. The Measured Quantity is normaly given in the original units; in cases where we have reinterpreted the original measurement, the listed value may differ from that given by the authors. The quoted uncertainty is the a priori uncertainty used as input when constructing the initial Thermochemical Network, and corresponds either to the value proposed by the original authors or to our estimate; if an additional multiplier is given in parentheses immediately after the prior uncertainty, it corresponds to the factor by which the prior uncertainty needed to be multiplied during the ATcT analysis in order to make that particular measurement consistent with the prevailing knowledge contained in the Thermochemical Network.

Contribution (%)	TN ID	Reaction	Measured Quantity	Reference
9.4	5624.3	CH2F2 (l) → CH2F2 (g)	Δ_rH°(245 K) = 20.48 ± 0.15 kJ/mol	Kanungo 1987, 2nd Law
7.7	5695.7	CF4 (g) + CH4 (g) → 2 CH2F2 (g)	Δ_rH°(0 K) = 107.8 ± 2.0 kJ/mol	Klopper 2010a, est unc
6.1	6656.1	CH2F2 (g) + O2 (g) → CO2 (g) + 2 HF (aq, 23 H2O)	Δ_rH°(298.15 K) = -139.83 ± 0.22 (×1.269) kcal/mol	Neugebauer 1958, as quoted by Cox 1970
5.6	5616.3	CH2F2 (g) → C (g) + 2 H (g) + 2 F (g)	Δ_rH°(0 K) = 416.24 ± 0.3 kcal/mol	Feller 2008
5.6	5615.11	CH2F2 (g) → C (g) + 2 H (g) + 2 F (g)	Δ_rH°(0 K) = 416.01 ± 0.30 kcal/mol	Sylvetsky 2016, Karton 2011
4.3	5622.6	2 CH2F2 (g) → CH3F (g) + CHF3 (g)	Δ_rH°(0 K) = -31.06 ± 2.0 kJ/mol	Csontos 2010
4.3	5622.7	2 CH2F2 (g) → CH3F (g) + CHF3 (g)	Δ_rH°(0 K) = -29.9 ± 2.0 kJ/mol	Klopper 2010a, est unc
3.6	5624.2	CH2F2 (l) → CH2F2 (g)	Δ_rH°(221.6 K) = 21.83 ± 0.24 kJ/mol	Kanungo 1987, 2nd Law
2.8	5696.7	CH3F (g) + CF4 (g) → CH2F2 (g) + CHF3 (g)	Δ_rH°(0 K) = 22.4 ± 2.0 kJ/mol	Klopper 2010a, est unc
2.2	5617.1	CH2F2 (g) → C (g) + H2 (g) + F2 (g)	Δ_rH°(0 K) = 1154.24 ± 2.0 kJ/mol	Csontos 2010
2.1	5695.6	CF4 (g) + CH4 (g) → 2 CH2F2 (g)	Δ_rH°(0 K) = 25.56 ± 0.9 kcal/mol	Ruscic W1RO
1.7	5695.4	CF4 (g) + CH4 (g) → 2 CH2F2 (g)	Δ_rH°(0 K) = 25.58 ± 1.0 kcal/mol	Ruscic G4
1.6	5620.6	CH2F2 (g) + 2 F (g) → CF4 (g) + 2 H (g)	Δ_rH°(0 K) = -207.81 ± 2.0 kJ/mol	Csontos 2010
1.5	5621.7	CH2F2 (g) + H (g) → CH3F (g) + F (g)	Δ_rH°(0 K) = 79.0 ± 2.0 kJ/mol	Klopper 2010a, est unc
1.5	5621.6	CH2F2 (g) + H (g) → CH3F (g) + F (g)	Δ_rH°(0 K) = 75.39 ± 2.0 kJ/mol	Csontos 2010
1.4	5695.3	CF4 (g) + CH4 (g) → 2 CH2F2 (g)	Δ_rH°(0 K) = 25.47 ± 1.1 kcal/mol	Ruscic G3X
1.2	5622.5	2 CH2F2 (g) → CH3F (g) + CHF3 (g)	Δ_rH°(0 K) = -7.33 ± 0.9 kcal/mol	Ruscic W1RO
1.2	5694.9	CHF3 (g) + CH4 (g) → CH2F2 (g) + CH3F (g)	Δ_rH°(0 K) = 85.4 ± 2.0 kJ/mol	Klopper 2010a, est unc
1.1	5616.4	CH2F2 (g) → C (g) + 2 H (g) + 2 F (g)	Δ_rH°(0 K) = 1742.3 ± 2.8 kJ/mol	Klopper 2010a
1.0	5695.5	CF4 (g) + CH4 (g) → 2 CH2F2 (g)	Δ_rH°(0 K) = 24.82 ± 1.3 kcal/mol	Ruscic CBS-n

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CH2F2 (l)

Please note: The correlation coefficients are obtained by renormalizing the off-diagonal elements of the covariance matrix by the corresponding variances.
The correlation coefficient is a number from -1 to 1, with 1 representing perfectly correlated species, -1 representing perfectly anti-correlated species, and 0 representing perfectly uncorrelated species.

Correlation Coefficent (%)	Species Name	Formula	Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units	Relative Molecular Mass	ATcT ID
93.1	Difluoromethane	CH2F2 (g)	-443.38	-450.99	± 0.33	kJ/mol	52.02339 ± 0.00081	75-10-5*0
66.0	Difluorobromomethane	CHF2Br (g)	-411.12	-424.31	± 0.46	kJ/mol	130.9194 ± 0.0013	1511-62-2*0
35.4	Fluoroform	CHF3 (g)	-689.34	-696.29	± 0.38	kJ/mol	70.01385 ± 0.00080	75-46-7*0
33.2	Fluoroform	CHF3 (l)		-704.76	± 0.41	kJ/mol	70.01385 ± 0.00080	75-46-7*590
24.6	Fluoromethane	CH3F (g)	-227.48	-235.51	± 0.23	kJ/mol	34.03292 ± 0.00083	593-53-3*0
20.2	Tetrafluoromethane	CF4 (g)	-927.77	-933.74	± 0.23	kJ/mol	88.00431 ± 0.00080	75-73-0*0
16.7	Polytetrafluoroethylene	CF2CF2 (s)		-830.20	± 0.55	kJ/mol	100.0150 ± 0.0016	9002-84-0*591
12.3	Fluoromethane	CH3F (l)		-245.78	± 0.45	kJ/mol	34.03292 ± 0.00083	593-53-3*590
10.8	Bromotrifluoromethane	CF3Br (g)	-638.73	-650.84	± 0.40	kJ/mol	148.9099 ± 0.0013	75-63-8*0
10.1	Iodotrifluoromethane	CF3I (g)	-583.30	-589.18	± 0.45	kJ/mol	195.91038 ± 0.00080	2314-97-8*0

Most Influential reactions involving CH2F2 (l)

Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.

Influence Coefficient	TN ID	Reaction	Measured Quantity	Reference
0.715	5624.3	CH2F2 (l) → CH2F2 (g)	Δ_rH°(245 K) = 20.48 ± 0.15 kJ/mol	Kanungo 1987, 2nd Law
0.279	5624.2	CH2F2 (l) → CH2F2 (g)	Δ_rH°(221.6 K) = 21.83 ± 0.24 kJ/mol	Kanungo 1987, 2nd Law
0.005	5624.1	CH2F2 (l) → CH2F2 (g)	Δ_rH°(221.43 K) = 19.89 ± 0.14 (×12.34) kJ/mol	ThermoData 2004

References

1		B. Ruscic, R. E. Pinzon, M. L. Morton, G. von Laszewski, S. Bittner, S. G. Nijsure, K. A. Amin, M. Minkoff, and A. F. Wagner, Introduction to Active Thermochemical Tables: Several "Key" Enthalpies of Formation Revisited. J. Phys. Chem. A 108, 9979-9997 (2004) [DOI: 10.1021/jp047912y]
2		B. Ruscic, R. E. Pinzon, G. von Laszewski, D. Kodeboyina, A. Burcat, D. Leahy, D. Montoya, and A. F. Wagner, Active Thermochemical Tables: Thermochemistry for the 21^st Century. J. Phys. Conf. Ser. 16, 561-570 (2005) [DOI: 10.1088/1742-6596/16/1/078]
3		B. Ruscic and D. H. Bross, Active Thermochemical Tables (ATcT) values based on ver. 1.124 of the Thermochemical Network, Argonne National Laboratory, Lemont, Illinois 2022; available at ATcT.anl.gov [DOI: 10.17038/CSE/1885923]
4		Y. Ren, L. Zhou, A. Mellouki, V. Daële, M. Idir, S. S. Brown, B. Ruscic, Robert S. Paton, M. R. McGillen, and A. R. Ravishankara, Reactions of NO3 with Aromatic Aldehydes: Gas-Phase Kinetics and Insights into the Mechanism of the Reaction. Atmos. Chem. Phys. 21, 13537-13551 (2021) [DOI: 10.5194/acp2021-228]
5		B. Ruscic and D. H. Bross, Active Thermochemical Tables: The Thermophysical and Thermochemical Properties of Methyl, CH3, and Methylene, CH2, Corrected for Nonrigid Rotor and Anharmonic Oscillator Effects. Mol. Phys. e1969046 (2021) [DOI: 10.1080/00268976.2021.1969046]
6		J. H. Thorpe, J. L. Kilburn, D. Feller, P. B. Changala, D. H. Bross, B. Ruscic, and J. F. Stanton, Elaborated Thermochemical Treatment of HF, CO, N2, and H2O: Insight into HEAT and Its Extensions J. Chem. Phys. 155, 184109 (2021) [DOI: 10.1063/5.0069322]
7		T. L. Nguyen, D. H. Bross, B. Ruscic, G. B. Ellison, and J. F. Stanton, Mechanism, Thermochemistry, and Kinetics of the Reversible Reactions: C2H3 + H2 ⇌ C2H4 + H ⇌ C2H5. Faraday Discuss. , (Advance Article) (2022) [DOI: 10.1039/D1FD00124H]
8		B. Ruscic, Uncertainty Quantification in Thermochemistry, Benchmarking Electronic Structure Computations, and Active Thermochemical Tables. Int. J. Quantum Chem. 114, 1097-1101 (2014) [DOI: 10.1002/qua.24605]
9		B. Ruscic and D. H. Bross, Thermochemistry Computer Aided Chem. Eng. 45, 3-114 (2019) [DOI: 10.1016/B978-0-444-64087-1.00001-2]

Formula

The aggregate state is given in parentheses following the formula, such as: g - gas-phase, cr - crystal, l - liquid, etc.

Uncertainties

The listed uncertainties correspond to estimated 95% confidence limits, as customary in thermochemistry (see, for example, Ruscic [8,9]).
Note that an uncertainty of ± 0.000 kJ/mol indicates that the estimated uncertainty is < ± 0.000₅ kJ/mol.

Website Functionality Credits

The reorganization of the website was developed and implemented by David H. Bross (ANL).
The find function is based on the complete Species Dictionary entries for the appropriate version of the ATcT TN.
The molecule images are rendered by Indigo-depict.
The XYZ renderings are based on Jmol: an open-source Java viewer for chemical structures in 3D. http://www.jmol.org/.

Acknowledgement

This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under Contract No. DE-AC02-06CH11357.