Selected ATcT [1, 2] enthalpy of formation based on version 1.156 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.148 to include species relevant to a recent study of the oxidation of ethylene [4] as well as new measurements that led to refining the thermochemistry of CF and SiF and their cations [5].

Ethynylene cation

Formula: [C2]+ (g)
CAS RN: 12595-79-8
ATcT ID: 12595-79-8*0
SMILES: [C]=[C+]
InChI: InChI=1S/C2/c1-2/q+1
InChIKey: ADIRGMFQWJHVBM-UHFFFAOYSA-N
Hills Formula: C2+

2D Image:

[C]=[C+]
Aliases: [C2]+; Ethynylene cation; Ethynylene ion (1+); Ethynyliumyl; 2-Ethynylium-1-yl; 1,2-Ethynediyl cation; 1,2-Ethynediyl ion (1+); Carbon dimer cation; Carbon dimer ion (1+); Diatomic carbon cation; Diatomic carbon ion (1+); Dicarbon cation; Dicarbon ion (1+); Carbon molecule cation; Carbon molecule ion (1+); Carbon cluster cation; Carbon cluster ion (1+)
Relative Molecular Mass: 24.0209 ± 0.0016

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
1964.971971.55± 0.40kJ/mol

3D Image of [C2]+ (g)

spin ON           spin OFF
          

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

The 3 contributors listed below account for 92.0% of the provenance of ΔfH° of [C2]+ (g).

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
61.32291.1 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.791 ± 0.005 eVKrechkivska 2016
15.32291.2 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.795 ± 0.010 eVHarper 2020
15.32291.3 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.790 ± 0.010 eVKrechkivska 2016

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
21.3 EthynyleneC2 (g, triplet)[C]=[C]827.222833.927± 0.085kJ/mol24.0214 ±
0.0016
12070-15-4*1
21.3 EthynyleneC2 (g, singlet)[C]=[C]819.999826.571± 0.085kJ/mol24.0214 ±
0.0016
12070-15-4*2
21.3 EthynyleneC2 (g)[C]=[C]819.999828.464± 0.085kJ/mol24.0214 ±
0.0016
12070-15-4*0
20.2 CarbonC (g, quintuplet)[C]1114.9631120.109± 0.040kJ/mol12.01070 ±
0.00080
7440-44-0*3
20.2 CarbonC (g, singlet)[C]833.331838.477± 0.040kJ/mol12.01070 ±
0.00080
7440-44-0*2
20.2 Carbon cationC+ (g)[C+]1797.8531803.451± 0.040kJ/mol12.01015 ±
0.00080
14067-05-1*0
20.2 CarbonC (g, triplet)[C]711.400716.885± 0.040kJ/mol12.01070 ±
0.00080
7440-44-0*1
20.2 CarbonC (g)[C]711.400716.885± 0.040kJ/mol12.01070 ±
0.00080
7440-44-0*0
20.2 Carbon dication[C]+2 (g)[C++]4150.4694155.616± 0.040kJ/mol12.00960 ±
0.00080
16092-61-8*0
20.1 Carbon anionC- (g)[C-]589.624594.770± 0.040kJ/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
0.6432291.1 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.791 ± 0.005 eVKrechkivska 2016
0.1602291.3 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.790 ± 0.010 eVKrechkivska 2016
0.1602291.2 C2 (g, triplet) → [C2]+ (g) ΔrH°(0 K) = 11.795 ± 0.010 eVHarper 2020
0.0102277.11 C2 (g) → [C2]+ (g) ΔrH°(0 K) = 11.880 ± 0.040 eVRuscic W1RO
0.0062284.1 [C2]+ (g) → C (g) C+ (g) ΔrH°(0 K) = 5.634 ± 0.050 eVShi 2013a, est unc
0.0032281.8 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -130.55 ± 1.50 kcal/molRuscic W1RO
0.0032281.4 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -129.24 ± 1.60 kcal/molRuscic G4
0.0032281.7 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -130.86 ± 1.60 kcal/molRuscic CBS-n
0.0022281.3 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -128.41 ± 1.72 kcal/molRuscic G3X
0.0012281.6 [C2]+ (g) → 2 C (g) ΔrH°(0 K) = -130.91 ± 2.16 kcal/molRuscic CBS-n
0.0012295.1 HCCH (g) → [C2]+ (g) H2 (g) ΔrH°(0 K) = 18.1 ± 0.1 (×1.091) eVHayaishi 1982
0.0002277.13 C2 (g) → [C2]+ (g) ΔrH°(0 K) = 11.771 ± 0.15 eVHarper 2020, est unc
0.0002277.12 C2 (g) → [C2]+ (g) ΔrH°(0 K) = 11.80 ± 0.15 eVFura 2002
0.0002277.3 C2 (g) → [C2]+ (g) ΔrH°(0 K) = 11.6 ± 0.4 eVGingerich 1994
0.0002277.2 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. 1.156 of the Thermochemical Network (2024); available at ATcT.anl.gov
4   N. A. Seifert, B. Ruscic, R. Sivaramakrishnan, and K. Prozument,
The C2H4O Isomers in the Oxidation of Ethylene
J. Mol. Spectrosc. 398, 111847/1-8 (2023) [DOI: 10.1016/j.jms.2023.111847]
5   U. Jacovella, B. Ruscic, N. L. Chen, H.-L. Le, S. Boyé-Péronne, S. Hartweg, M. Roy-Chowdhury, G. A. Garcia, J.-C. Loison, and B. Gans,
Refining Thermochemical Properties of CF, SiF, and Their Cations by Combining Photoelectron Spectroscopy, Quantum Chemical Calculations, and the Active Thermochemical Tables Approach
Phys. Chem. Chem. Phys. 25, 30838-30847 (2023) [DOI: 10.1039/D3CP04244H]
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]
7   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 [6] and Ruscic and Bross[7]).
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.