Selected ATcT [1, 2] enthalpy of formation based on version 1.122p of the Thermochemical Network [3] This version of ATcT results was generated from an expansion of version 1.122o [4] to include an updated enthalpy of formation for Hydrazine. [5].
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Species Name |
Formula |
Image |
ΔfH°(0 K) |
ΔfH°(298.15 K) |
Uncertainty |
Units |
Relative Molecular Mass |
ATcT ID |
Methyliumyl | [CH2]+ (g) | | 1393.20 | 1394.06 | ± 0.11 | kJ/mol | 14.02603 ± 0.00081 | 15091-72-2*0 |
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Representative Geometry of [CH2]+ (g) |
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spin ON spin OFF |
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Top contributors to the provenance of ΔfH° of [CH2]+ (g)The 20 contributors listed below account only for 57.2% of the provenance of ΔfH° of [CH2]+ (g). A total of 206 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.
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Contribution (%) | TN ID | Reaction | Measured Quantity | Reference | 11.1 | 1926.1 | CH2 (g, triplet) → [CH2]+ (g)  | ΔrH°(0 K) = 83772 ± 3 cm-1 | Willitsch 2002, Willitsch 2003 | 8.6 | 1923.9 | CH2 (g, triplet) → C (g) + 2 H (g)  | ΔrH°(0 K) = 179.80 ± 0.06 kcal/mol | Feller 2016, note unc2 | 6.3 | 1923.8 | CH2 (g, triplet) → C (g) + 2 H (g)  | ΔrH°(0 K) = 179.76 ± 0.07 kcal/mol | Feller 2014 | 5.4 | 1939.1 | CH3 (g) → CH2 (g, triplet) + H (g)  | ΔrH°(0 K) = 109.26 ± 0.08 kcal/mol | Feller 2016, est unc, note unc2 | 2.9 | 1888.1 | 2 H2 (g) + C (graphite) → CH4 (g)  | ΔrG°(1165 K) = 37.521 ± 0.068 kJ/mol | Smith 1946, note COf, 3rd Law | 2.4 | 1962.8 | CH2 (g, triplet) → CH (g) + H (g)  | ΔrH°(0 K) = 417.85 ± 0.35 kJ/mol | Csaszar 2003 | 2.4 | 1936.1 | CH3 (g) → [CH2]+ (g) + H (g)  | ΔrH°(0 K) = 15.120 ± 0.006 eV | Litorja 1998 | 1.9 | 1938.8 | CH3 (g) → CH2 (g, triplet) + H (g)  | ΔrH°(0 K) = 457.05 ± 0.56 kJ/mol | Harding 2008 | 1.7 | 1922.9 | CH2 (g, triplet) → C (g) + 2 H (g)  | ΔrH°(0 K) = 752.45 ± 0.56 kJ/mol | Harding 2008 | 1.5 | 1938.4 | CH3 (g) → CH2 (g, triplet) + H (g)  | ΔrH°(0 K) = 109.22 ± 0.15 kcal/mol | Karton 2008 | 1.5 | 1962.12 | CH2 (g, triplet) → CH (g) + H (g)  | ΔrH°(0 K) = 99.75 ± 0.08 (×1.325) kcal/mol | Feller 2014 | 1.3 | 1922.5 | CH2 (g, triplet) → C (g) + 2 H (g)  | ΔrH°(0 K) = 179.86 ± 0.15 kcal/mol | Karton 2008 | 1.3 | 1943.1 | [CH2]- (g) → C- (g) + 2 H (g)  | ΔrH°(0 K) = 165.69 ± 0.12 kcal/mol | Feller 2016, note unc2 | 1.3 | 1923.1 | CH2 (g, triplet) → C (g) + 2 H (g)  | ΔrH°(0 K) = 753.03 ± 0.62 (×1.022) kJ/mol | Csaszar 2003 | 1.2 | 1949.12 | CH (g) → C (g) + H (g)  | ΔrH°(0 K) = 80.01 ± 0.04 kcal/mol | Feller 2014 | 1.2 | 1938.6 | CH3 (g) → CH2 (g, triplet) + H (g)  | ΔrH°(0 K) = 457.05 ± 0.70 kJ/mol | Harding 2008 | 1.1 | 1810.2 | CO (g) → C+ (g) + O (g)  | ΔrH°(0 K) = 22.3713 ± 0.0015 eV | Ng 2007 | 1.1 | 2417.1 | CH3OH (g) → CH2 (g, triplet) + H2O (g)  | ΔrH°(0 K) = 81.77 ± 0.17 kcal/mol | Nguyen 2015a | 1.1 | 1925.9 | CH2 (g, singlet) → C (g) + 2 H (g)  | ΔrH°(0 K) = 170.98 ± 0.11 (×1.414) kcal/mol | Feller 2014 | 1.1 | 1922.7 | CH2 (g, triplet) → C (g) + 2 H (g)  | ΔrH°(0 K) = 752.43 ± 0.70 kJ/mol | Harding 2008 |
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Top 10 species with enthalpies of formation correlated to the ΔfH° of [CH2]+ (g) |
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.
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Correlation Coefficent (%) | Species Name | Formula | Image | ΔfH°(0 K) | ΔfH°(298.15 K) | Uncertainty | Units | Relative Molecular Mass | ATcT ID | 93.8 | Methylene | CH2 (g, triplet) | | 391.061 | 391.618 | ± 0.097 | kJ/mol | 14.02658 ± 0.00081 | 2465-56-7*1 | 93.8 | Methylene | CH2 (g) | | 391.061 | 391.618 | ± 0.097 | kJ/mol | 14.02658 ± 0.00081 | 2465-56-7*0 | 82.2 | Methylene | CH2 (g, singlet) | | 428.72 | 429.13 | ± 0.11 | kJ/mol | 14.02658 ± 0.00081 | 2465-56-7*2 | 80.3 | Ketene | CH2CO (g, singlet) | | -45.35 | -48.47 | ± 0.12 | kJ/mol | 42.0367 ± 0.0016 | 463-51-4*2 | 80.3 | Ketene | CH2CO (g) | | -45.35 | -48.47 | ± 0.12 | kJ/mol | 42.0367 ± 0.0016 | 463-51-4*0 | 80.1 | Ketene cation | [CH2CO]+ (g) | | 882.22 | 879.05 | ± 0.12 | kJ/mol | 42.0361 ± 0.0016 | 64999-16-2*0 | 42.4 | Methylene anion | [CH2]- (g) | | 328.17 | 328.60 | ± 0.19 | kJ/mol | 14.02713 ± 0.00081 | 50928-07-9*0 | 37.5 | Carbon atom | C (g) | | 711.397 | 716.882 | ± 0.047 | kJ/mol | 12.01070 ± 0.00080 | 7440-44-0*0 | 37.5 | Carbon atom | C (g, triplet) | | 711.397 | 716.882 | ± 0.047 | kJ/mol | 12.01070 ± 0.00080 | 7440-44-0*1 | 37.5 | Carbon atom | C (g, singlet) | | 833.328 | 838.474 | ± 0.047 | kJ/mol | 12.01070 ± 0.00080 | 7440-44-0*2 |
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Most Influential reactions involving [CH2]+ (g)Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.
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Influence Coefficient | TN ID | Reaction | Measured Quantity | Reference | 0.988 | 1926.1 | CH2 (g, triplet) → [CH2]+ (g)  | ΔrH°(0 K) = 83772 ± 3 cm-1 | Willitsch 2002, Willitsch 2003 | 0.353 | 2709.5 | CH3CCH3 (g, singlet) + [CH2]+ (g) → [CH3CCH3]+ (g) + CH2 (g, singlet)  | ΔrH°(0 K) = -2.295 ± 0.027 eV | Ruscic W1RO | 0.107 | 2709.2 | CH3CCH3 (g, singlet) + [CH2]+ (g) → [CH3CCH3]+ (g) + CH2 (g, singlet)  | ΔrH°(0 K) = -2.315 ± 0.049 eV | Ruscic G4 | 0.102 | 2709.4 | CH3CCH3 (g, singlet) + [CH2]+ (g) → [CH3CCH3]+ (g) + CH2 (g, singlet)  | ΔrH°(0 K) = -2.318 ± 0.050 eV | Ruscic CBS-n | 0.067 | 2709.1 | CH3CCH3 (g, singlet) + [CH2]+ (g) → [CH3CCH3]+ (g) + CH2 (g, singlet)  | ΔrH°(0 K) = -2.282 ± 0.062 eV | Ruscic G3X | 0.059 | 2709.3 | CH3CCH3 (g, singlet) + [CH2]+ (g) → [CH3CCH3]+ (g) + CH2 (g, singlet)  | ΔrH°(0 K) = -2.289 ± 0.066 eV | Ruscic CBS-n | 0.033 | 1936.1 | CH3 (g) → [CH2]+ (g) + H (g)  | ΔrH°(0 K) = 15.120 ± 0.006 eV | Litorja 1998 | 0.006 | 3374.2 | CH2CO (g) → [CH2]+ (g) + CO (g)  | ΔrH°(0 K) = 13.729 ± 0.008 eV | McCulloh 1976a | 0.002 | 3374.1 | CH2CO (g) → [CH2]+ (g) + CO (g)  | ΔrH°(0 K) = 13.743 ± 0.005 (×2.65) eV | Ruscic 1999 | 0.001 | 1926.3 | CH2 (g, triplet) → [CH2]+ (g)  | ΔrH°(0 K) = 10.396 ± 0.003 (×3.221) eV | Herzberg 1959, Herzberg 1961a, Herzberg 1971 | 0.001 | 1927.11 | CH2 (g, triplet) → [CH2]+ (g)  | ΔrH°(0 K) = 10.382 ± 0.010 eV | Lau 2005 | 0.001 | 1926.2 | CH2 (g, triplet) → [CH2]+ (g)  | ΔrH°(0 K) = 10.393 ± 0.011 eV | Litorja 1998 | 0.001 | 1936.2 | CH3 (g) → [CH2]+ (g) + H (g)  | ΔrH°(0 K) = 15.09 ± 0.03 (×1.189) eV | Chupka 1968a | 0.000 | 1936.3 | CH3 (g) → [CH2]+ (g) + H (g)  | ΔrH°(0 K) = 15.121 ± 0.040 eV | Ruscic W1RO | 0.000 | 1930.8 | [CH2]+ (g) → C (g) + 2 H (g)  | ΔrH°(0 K) = -59.60 ± 1 kcal/mol | Matus 2006 | 0.000 | 3374.10 | CH2CO (g) → [CH2]+ (g) + CO (g)  | ΔrH°(0 K) = 13.720 ± 0.040 eV | Ruscic W1RO | 0.000 | 1930.9 | [CH2]+ (g) → C (g) + 2 H (g)  | ΔrH°(0 K) = -59.17 ± 1.50 kcal/mol | Ruscic W1RO | 0.000 | 1930.7 | [CH2]+ (g) → C (g) + 2 H (g)  | ΔrH°(0 K) = -59.73 ± 1.60 kcal/mol | Ruscic CBS-n | 0.000 | 1930.4 | [CH2]+ (g) → C (g) + 2 H (g)  | ΔrH°(0 K) = -59.07 ± 1.60 kcal/mol | Ruscic G4 | 0.000 | 1966.1 | [CH2]+ (g) → CH (g) + H+ (g)  | ΔrH°(0 K) = 174.08 ± 2.0 kcal/mol | Raabe 2007, est unc |
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References
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1
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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]
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2
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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 21st Century.
J. Phys. Conf. Ser. 16, 561-570 (2005)
[DOI: 10.1088/1742-6596/16/1/078]
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3
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B. Ruscic and D. H. Bross, Active Thermochemical Tables (ATcT) values based on ver. 1.122p of the Thermochemical Network (2020); available at ATcT.anl.gov |
4
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P. B. Changala, T. L. Nguyen, J. H. Baraban, G. B. Ellison, J. F. Stanton, D. H. Bross, and B. Ruscic,
Active Thermochemical Tables: The Adiabatic Ionization Energy of Hydrogen Peroxide.
J. Phys. Chem. A 121, 8799-8806 (2017)
[DOI: 10.1021/acs.jpca.7b06221] (highlighted on the journal cover)
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5
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D. Feller, D. H. Bross, and B. Ruscic,
Enthalpy of Formation of N2H4 (Hydrazine) Revisited.
J. Phys. Chem. A 121, 6187-6198 (2017)
[DOI: 10.1021/acs.jpca.7b06017]
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6
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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]
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Formula
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The aggregate state is given in parentheses following the formula, such as: g - gas-phase, cr - crystal, l - liquid, etc.
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Uncertainties
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The listed uncertainties correspond to estimated 95% confidence limits, as customary in thermochemistry (see, for example, Ruscic [6]).
Note that an uncertainty of ± 0.000 kJ/mol indicates that the estimated uncertainty is < ± 0.0005 kJ/mol.
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Website Functionality Credits
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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/.
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Acknowledgement
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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.
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