Selected ATcT [1, 2] enthalpy of formation based on version 1.176 of the Thermochemical Network [3]This version of ATcT results[3] was generated by additional expansion of version 1.172 to include species related to Criegee intermediates that are involved in several ongoing studies[4].
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Ethynylene |
Formula: C2 (g, triplet) |
CAS RN: 12070-15-4 |
ATcT ID: 12070-15-4*1 |
SMILES: [C]=[C] |
InChI: InChI=1S/C2/c1-2 |
InChIKey: LBVWYGNGGJURHQ-UHFFFAOYSA-N |
Hills Formula: C2 |
2D Image: |
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Aliases: C2; Ethynylene; Ethynediyl; 1,2-Ethynediyl; Carbon dimer; Diatomic carbon; Dicarbon radical; Dicarbon; Carbon molecule; Carbon cluster |
Relative Molecular Mass: 24.0214 ± 0.0016 |
ΔfH°(0 K) | ΔfH°(298.15 K) | Uncertainty | Units |
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827.185 | 833.890 | ± 0.082 | kJ/mol |
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3D Image of C2 (g, triplet) |
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spin ON spin OFF |
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Top contributors to the provenance of ΔfH° of C2 (g, triplet)The 20 contributors listed below account only for 47.9% of the provenance of ΔfH° of C2 (g, triplet). A total of 873 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 | 11.3 | 2306.1 | C2 (g, triplet) → 2 C (g)  | ΔrH°(0 K) = 49786.7 ± 2.4 cm-1 | Borsovszky 2021, Schmidt 2020, Haris 2017 | 8.2 | 2268.11 | CO (g) → C (g) + O (g)  | ΔrH°(0 K) = 1071.92 ± 0.10 kJ/mol | Thorpe 2021 | 4.8 | 2375.1 | 2 H2 (g) + C (graphite) → CH4 (g)  | ΔrG°(1165 K) = 37.521 ± 0.068 kJ/mol | Smith 1946, note COf, 3rd Law | 3.9 | 2278.2 | CO (g) → C+ (g) + O (g)  | ΔrH°(0 K) = 22.3713 ± 0.0015 eV | Ng 2007 | 3.6 | 2286.9 | C (graphite) + CO2 (g) → 2 CO (g)  | ΔrG°(1165 K) = -33.545 ± 0.058 kJ/mol | Smith 1946, note COf, 3rd Law | 2.5 | 125.2 | 1/2 O2 (g) + H2 (g) → H2O (cr,l)  | ΔrH°(298.15 K) = -285.8261 ± 0.040 kJ/mol | Rossini 1939, Rossini 1931, Rossini 1931b, note H2Oa, Rossini 1930 | 2.3 | 2228.7 | C (graphite) + O2 (g) → CO2 (g)  | ΔrH°(298.15 K) = -393.464 ± 0.024 kJ/mol | Hawtin 1966, note CO2e | 2.0 | 2262.1 | CO (g) → C (g) + O (g)  | ΔrH°(0 K) = 89597.3 ± 12.0 (×1.384) cm-1 | Kepa 2014, note unc2 | 1.1 | 2262.2 | CO (g) → C (g) + O (g)  | ΔrH°(0 K) = 89592 ± 15 (×1.477) cm-1 | Eidelsberg 1987 | 0.9 | 2228.4 | C (graphite) + O2 (g) → CO2 (g)  | ΔrH°(298.15 K) = -393.462 ± 0.038 kJ/mol | Lewis 1965, note CO2d | 0.9 | 2228.5 | C (graphite) + O2 (g) → CO2 (g)  | ΔrH°(298.15 K) = -393.468 ± 0.038 kJ/mol | Fraser 1952, note CO2f | 0.7 | 6863.8 | C6H6 (g) → 6 C (g) + 6 H (g)  | ΔrH°(0 K) = 5463.0 ± 1.8 kJ/mol | Harding 2011 | 0.7 | 2265.5 | CO (g) → C (g) + O (g)  | ΔrH°(0 K) = 89632 ± 27 cm-1 | Ruscic 2003 | 0.6 | 2261.3 | CO (g) → C (g) + O (g)  | ΔrH°(0 K) = 89620 ± 29 cm-1 | Douglas 1955, Schmid 1935, note COj | 0.6 | 9265.1 | C60 (cr,l) + 60 O2 (g) → 60 CO2 (g)  | ΔrH°(298.15 K) = -25965 ± 20 kJ/mol | Kolesov 1996, est unc | 0.6 | 2228.11 | C (graphite) + O2 (g) → CO2 (g)  | ΔrH°(298.15 K) = -94.051 ± 0.011 kcal/mol | Prosen 1944a, Cox 1970, NBS TN270, NBS Tables 1989 | 0.6 | 2529.1 | CH2CH2 (g) + 3 O2 (g) → 2 CO2 (g) + 2 H2O (cr,l)  | ΔrH°(298.15 K) = -1411.18 ± 0.30 kJ/mol | Rossini 1937 | 0.5 | 9229.6 | C6H4(C2H2(CC(C4H4))) (g) → 14 C (g) + 10 H (g)  | ΔrH°(0 K) = 11890.6 ± 5.2 kJ/mol | Karton 2021 | 0.5 | 6863.5 | C6H6 (g) → 6 C (g) + 6 H (g)  | ΔrH°(0 K) = 1305.43 ± 0.50 kcal/mol | Karton 2017 | 0.5 | 9225.6 | C6H4(CH(CC(C4H4)CH)) (g) → 14 C (g) + 10 H (g)  | ΔrH°(0 K) = 11866.6 ± 5.2 kJ/mol | Karton 2021, Karton 2012a |
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Top 10 species with enthalpies of formation correlated to the ΔfH° of C2 (g, triplet) |
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 | 100.0 | Ethynylene | C2 (g, singlet) | | 819.961 | 826.534 | ± 0.082 | kJ/mol | 24.0214 ± 0.0016 | 12070-15-4*2 | 100.0 | Ethynylene | C2 (g) | | 819.961 | 828.427 | ± 0.082 | kJ/mol | 24.0214 ± 0.0016 | 12070-15-4*0 | 93.8 | Carbon | C (g) | | 711.381 | 716.866 | ± 0.039 | kJ/mol | 12.01070 ± 0.00080 | 7440-44-0*0 | 93.8 | Carbon | C (g, triplet) | | 711.381 | 716.866 | ± 0.039 | kJ/mol | 12.01070 ± 0.00080 | 7440-44-0*1 | 93.8 | Carbon cation | C+ (g) | | 1797.834 | 1803.432 | ± 0.039 | kJ/mol | 12.01015 ± 0.00080 | 14067-05-1*0 | 93.8 | Carbon | C (g, quintuplet) | | 1114.944 | 1120.091 | ± 0.039 | kJ/mol | 12.01070 ± 0.00080 | 7440-44-0*3 | 93.8 | Carbon | C (g, singlet) | | 833.312 | 838.459 | ± 0.039 | kJ/mol | 12.01070 ± 0.00080 | 7440-44-0*2 | 93.7 | Carbon dication | [C]+2 (g) | | 4150.451 | 4155.597 | ± 0.039 | kJ/mol | 12.00960 ± 0.00080 | 16092-61-8*0 | 93.4 | Carbon anion | C- (g) | | 589.605 | 594.751 | ± 0.039 | kJ/mol | 12.01125 ± 0.00080 | 14337-00-9*0 | 92.3 | Methyliumylidene | [CH]+ (g) | | 1619.738 | 1623.081 | ± 0.039 | kJ/mol | 13.01809 ± 0.00080 | 24361-82-8*0 |
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Most Influential reactions involving C2 (g, triplet)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 | 1.000 | 2305.1 | C2 (g, singlet) → C2 (g, triplet)  | ΔrH°(0 K) = 603.817 ± 0.02 cm-1 | Furtenbacher 2016, Chen 2015, est unc | 0.968 | 2306.1 | C2 (g, triplet) → 2 C (g)  | ΔrH°(0 K) = 49786.7 ± 2.4 cm-1 | Borsovszky 2021, Schmidt 2020, Haris 2017 | 0.643 | 2307.1 | C2 (g, triplet) → [C2]+ (g)  | ΔrH°(0 K) = 11.791 ± 0.005 eV | Krechkivska 2016 | 0.160 | 2307.3 | C2 (g, triplet) → [C2]+ (g)  | ΔrH°(0 K) = 11.790 ± 0.010 eV | Krechkivska 2016 | 0.160 | 2307.2 | C2 (g, triplet) → [C2]+ (g)  | ΔrH°(0 K) = 11.795 ± 0.010 eV | Harper 2020 | 0.013 | 2306.2 | C2 (g, triplet) → 2 C (g)  | ΔrH°(0 K) = 49790 ± 20 cm-1 | Borsovszky 2021, Chen 2015 | 0.000 | 2306.3 | C2 (g, triplet) → 2 C (g)  | ΔrH°(0 K) = 49542 ± 303 cm-1 | Welsh 2017, Furtenbacher 2016, Martin 1998 | 0.000 | 2305.5 | C2 (g, singlet) → C2 (g, triplet)  | ΔrH°(0 K) = 601.3 ± 5 cm-1 | Martin 1992b, Tanabashi 2007, Davis 1988, Davis 1988a, Douay 1988a, est unc | 0.000 | 2305.3 | C2 (g, singlet) → C2 (g, triplet)  | ΔrH°(0 K) = 599.39 ± 5 cm-1 | Huber 1979, est unc | 0.000 | 2305.4 | C2 (g, singlet) → C2 (g, triplet)  | ΔrH°(0 K) = 597.26 ± 5 (×1.325) cm-1 | Dhumwad 1981, Huber 1979, est unc | 0.000 | 2305.7 | C2 (g, singlet) → C2 (g, triplet)  | ΔrH°(0 K) = 0.079 ± 0.005 eV | Harper 2020, 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. 1.176 of the Thermochemical Network (2024); available at ATcT.anl.gov |
4
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T. L. Nguyen et al, ongoing studies (2024)
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5
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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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6
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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]
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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 [5] and Ruscic and Bross[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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