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].

Species Name Formula Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
Molecular
Mass		 ATcT ID
Ethynylene cation[C2]+ (g)[C]=[C+]1965.161971.74± 0.50kJ/mol24.0209 ±
0.0016		12595-79-8*0

Representative Geometry of [C2]+ (g)

spin ON           spin OFF
          

Top contributors to the provenance of ΔfH° of [C2]+ (g)

The 20 contributors listed below account only for 89.9% of the provenance of ΔfH° of [C2]+ (g).
A total of 21 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
55.31834.1 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.791 ± 0.005 eVKrechkivska 2016
13.81834.2 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.788 ± 0.010 eVKrechkivska 2016
3.41823.10 C2 (g) → 2 C (g) ΔrH°(0 K) = 144.07 ± 0.15 kcal/molKarton 2007a, Karton 2008, Karton 2009
3.21837.7 HCCH (g) → 2 H (g) + C2 (g) ΔrH°(0 K) = 244.65 ± 0.15 kcal/molKarton 2007a
2.11824.10 C2 (g) → 2 C (g) ΔrH°(0 K) = 144.19 ± 0.19 kcal/molFeller 2014
1.21823.9 C2 (g) → 2 C (g) ΔrH°(0 K) = 144.08 ± 0.25 kcal/molKarton 2007a, Karton 2009
0.91830.1 [C2]+ (g) → C (g) + C+ (g) ΔrH°(0 K) = 5.634 ± 0.050 eVShi 2013a, est unc
0.81824.9 C2 (g) → 2 C (g) ΔrH°(0 K) = 143.89 ± 0.3 kcal/molFeller 2008
0.81823.8 C2 (g) → 2 C (g) ΔrH°(0 K) = 144.05 ± 0.30 kcal/molKarton 2009, Karton 2007a
0.81823.7 C2 (g) → 2 C (g) ΔrH°(0 K) = 143.88 ± 0.30 kcal/molKarton 2009, Karton 2007a, Karton 2011
0.81825.10 C2 (g) → [C2]+ (g) ΔrH°(0 K) = 11.880 ± 0.040 eVRuscic W1RO
0.81822.8 C2 (g) → 2 C (g) ΔrH°(0 K) = 143.7 ± 0.3 (×1.022) kcal/molFeller 2007
0.81837.5 HCCH (g) → 2 H (g) + C2 (g) ΔrH°(0 K) = 244.86 ± 0.30 kcal/molKarton 2006, Karton 2007a
0.81837.8 HCCH (g) → 2 H (g) + C2 (g) ΔrH°(0 K) = 244.62 ± 0.3 kcal/molFeller 2008
0.81837.6 HCCH (g) → 2 H (g) + C2 (g) ΔrH°(0 K) = 244.69 ± 0.30 kcal/molKarton 2006, Karton 2007a
0.72143.5 CCH (g) → C2 (g) + H (g) ΔrH°(0 K) = 113.22 ± 0.30 (×1.022) kcal/molKarton 2011
0.51828.8 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -130.55 ± 1.50 kcal/molRuscic W1RO
0.51828.4 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -129.24 ± 1.60 kcal/molRuscic G4
0.51828.7 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -130.86 ± 1.60 kcal/molRuscic CBS-n
0.41823.6 C2 (g) → 2 C (g) ΔrH°(0 K) = 143.93 ± 0.40 kcal/molKarton 2009, Karton 2007a, Karton 2011

Top 10 species with enthalpies of formation correlated to the ΔfH° of [C2]+ (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.

Correlation
Coefficent
(%)		Species Name Formula Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
Molecular
Mass		 ATcT ID
51.4 EthynyleneC2 (g, triplet)[C]=[C]827.50834.21± 0.26kJ/mol24.0214 ±
0.0016		12070-15-4*1
51.4 EthynyleneC2 (g, singlet)[C]=[C]820.28826.85± 0.26kJ/mol24.0214 ±
0.0016		12070-15-4*2
51.4 EthynyleneC2 (g)[C]=[C]820.28828.75± 0.26kJ/mol24.0214 ±
0.0016		12070-15-4*0
34.0 Carbide[C2]- (g)[C]=[C-]504.69511.27± 0.39kJ/mol24.0219 ±
0.0016		12595-78-7*0
17.8 Carbon cationC+ (g)[C+]1797.8491803.447± 0.047kJ/mol12.01015 ±
0.00080		14067-05-1*0
17.8 Carbon atomC (g, singlet)[C]833.328838.474± 0.047kJ/mol12.01070 ±
0.00080		7440-44-0*2
17.8 Carbon atomC (g, quintuplet)[C]1114.9591120.106± 0.047kJ/mol12.01070 ±
0.00080		7440-44-0*3
17.8 Carbon atomC (g, triplet)[C]711.397716.882± 0.047kJ/mol12.01070 ±
0.00080		7440-44-0*1
17.8 Carbon atomC (g)[C]711.397716.882± 0.047kJ/mol12.01070 ±
0.00080		7440-44-0*0
17.7 Carbon anionC- (g)[C-]589.620594.766± 0.047kJ/mol12.01125 ±
0.00080		14337-00-9*0

Most Influential reactions involving [C2]+ (g)

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
0.7671834.1 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.791 ± 0.005 eVKrechkivska 2016
0.1911834.2 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.788 ± 0.010 eVKrechkivska 2016
0.0121825.10 C2 (g) → [C2]+ (g) ΔrH°(0 K) = 11.880 ± 0.040 eVRuscic W1RO
0.0101830.1 [C2]+ (g) → C (g) + C+ (g) ΔrH°(0 K) = 5.634 ± 0.050 eVShi 2013a, est unc
0.0061828.8 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -130.55 ± 1.50 kcal/molRuscic W1RO
0.0051828.4 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -129.24 ± 1.60 kcal/molRuscic G4
0.0051828.7 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -130.86 ± 1.60 kcal/molRuscic CBS-n
0.0041828.3 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -128.41 ± 1.72 kcal/molRuscic G3X
0.0021828.6 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -130.91 ± 2.16 kcal/molRuscic CBS-n
0.0021838.1 HCCH (g) → [C2]+ (g) + H2 (g) ΔrH°(0 K) = 18.1 ± 0.1 (×1.044) eVHayaishi 1982
0.0001825.11 C2 (g) → [C2]+ (g) ΔrH°(0 K) = 11.80 ± 0.15 eVFura 2002
0.0001825.2 C2 (g) → [C2]+ (g) ΔrH°(0 K) = 11.6 ± 0.4 eVGingerich 1994
0.0001825.1 C2 (g) → [C2]+ (g) ΔrH°(0 K) = 11.4 ± 0.3 (×1.576) eVReid 1995
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 21st 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. 1.122p of the Thermochemical Network (2020); available at ATcT.anl.gov
4   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)
5   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]
6   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]
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 [6]).
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.