Selected ATcT [1, 2] enthalpy of formation based on version 1.130 of the Thermochemical Network [3]

This version of ATcT results[4] was generated by additional expansion of version 1.128 [5,6] to include with the calculations provided in reference [4].

Carbide

Formula: [C2]- (g)

CAS RN: 12595-78-7

ATcT ID: 12595-78-7*0

SMILES: [C]=[C-]

InChI: InChI=1S/C2/c1-2/q-1

InChIKey: XHWLRFQJZNQFGO-UHFFFAOYSA-N

Hills Formula: C2-

2D Image:

Aliases: [C2]-; Carbide; Carbide ion; Carbide anion; Carbide ion (1-); Ethynylene anion; Ethynylene ion (1-); 1,2-Ethynediyl anion; 1,2-Ethynediyl ion (1-); 2-Ethynidyl; Carbon dimer anion; Carbon dimer ion (1-); Diatomic carbon anion; Diatomic carbon ion (1-); Dicarbon anion; Dicarbon ion (1-); Carbon molecule anion; Carbon molecule ion (1-); Carbon cluster anion; Carbon cluster ion (1-)

Relative Molecular Mass: 24.0219 ± 0.0016

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
504.40	510.98	± 0.31	kJ/mol

3D Image of [C2]- (g)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of [C2]- (g)

The 4 contributors listed below account for 90.1% of the provenance of Δ_fH° 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
52.7	2199.1	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.272 ± 0.004 eV	Feller 2016, note unc2
23.4	2198.2	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.269 ± 0.006 eV	Ervin 1991
13.1	2198.1	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.273 ± 0.008 eV	Arnold 1991
0.8	2210.1	C2 (g, triplet) → 2 C (g)	Δ_rH°(0 K) = 49786.7 ± 2.4 cm-1	Borsovszky 2021, Schmidt 2020, Haris 2017

Top 10 species with enthalpies of formation correlated to the Δ_fH° 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	Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units	Relative Molecular Mass	ATcT ID
28.3	Ethynylene	C2 (g)	819.991	828.457	± 0.087	kJ/mol	24.0214 ± 0.0016	12070-15-4*0
28.3	Ethynylene	C2 (g, singlet)	819.991	826.564	± 0.087	kJ/mol	24.0214 ± 0.0016	12070-15-4*2
28.3	Ethynylene	C2 (g, triplet)	827.214	833.919	± 0.087	kJ/mol	24.0214 ± 0.0016	12070-15-4*1
26.8	Carbon cation	C+ (g)	1797.849	1803.447	± 0.041	kJ/mol	12.01015 ± 0.00080	14067-05-1*0
26.8	Carbon	C (g, quintuplet)	1114.959	1120.105	± 0.041	kJ/mol	12.01070 ± 0.00080	7440-44-0*3
26.8	Carbon	C (g, singlet)	833.327	838.474	± 0.041	kJ/mol	12.01070 ± 0.00080	7440-44-0*2
26.8	Carbon	C (g, triplet)	711.396	716.881	± 0.041	kJ/mol	12.01070 ± 0.00080	7440-44-0*1
26.8	Carbon	C (g)	711.396	716.881	± 0.041	kJ/mol	12.01070 ± 0.00080	7440-44-0*0
26.8	Carbon dication	[C]+2 (g)	4150.466	4155.612	± 0.041	kJ/mol	12.00960 ± 0.00080	16092-61-8*0
26.7	Carbon anion	C- (g)	589.620	594.766	± 0.041	kJ/mol	12.01125 ± 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
0.786	2129.1	[C2]- (g) → 2 [C]-4 (g)	Δ_rH°(0 K) = 50.968 ± 0.061 eV	Ruscic G4
0.573	2199.1	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.272 ± 0.004 eV	Feller 2016, note unc2
0.431	2200.5	[C2]-2 (g) → [C2]- (g)	Δ_rH°(0 K) = -3.520 ± 0.050 eV	Ruscic W1RO
0.289	2200.2	[C2]-2 (g) → [C2]- (g)	Δ_rH°(0 K) = -3.450 ± 0.061 eV	Ruscic G4
0.254	2198.2	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.269 ± 0.006 eV	Ervin 1991
0.143	2198.1	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.273 ± 0.008 eV	Arnold 1991
0.133	2200.4	[C2]-2 (g) → [C2]- (g)	Δ_rH°(0 K) = -3.491 ± 0.090 eV	Ruscic CBS-n
0.092	2200.1	[C2]-2 (g) → [C2]- (g)	Δ_rH°(0 K) = -3.616 ± 0.085 (×1.269) eV	Ruscic G3X
0.047	2200.3	[C2]-2 (g) → [C2]- (g)	Δ_rH°(0 K) = -3.659 ± 0.092 (×1.646) eV	Ruscic CBS-n
0.008	2129.3	[C2]- (g) → 2 [C]-4 (g)	Δ_rH°(0 K) = 50.361 ± 0.090 (×6.442) eV	Ruscic CBS-n
0.006	2200.6	[C2]-2 (g) → [C2]- (g)	Δ_rH°(0 K) = -3.2 ± 0.4 eV	Sommerfeld 1997, est unc
0.005	2199.2	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.264 ± 0.043 eV	Lu 2004
0.003	2198.13	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.261 ± 0.050 eV	Ruscic W1RO
0.002	2199.3	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.29 ± 0.06 eV	Sordo 2001, est unc, Huber 1979
0.002	2202.8	[C2]- (g) → 2 C (g)	Δ_rH°(0 K) = 218.61 ± 1.50 kcal/mol	Ruscic W1RO
0.001	2202.4	[C2]- (g) → 2 C (g)	Δ_rH°(0 K) = 220.26 ± 1.60 kcal/mol	Ruscic G4
0.001	2202.7	[C2]- (g) → 2 C (g)	Δ_rH°(0 K) = 218.42 ± 1.60 kcal/mol	Ruscic CBS-n
0.001	2205.1	[C2]- (g) → C (g) + C- (g)	Δ_rH°(0 K) = 188.7 ± 1.5 (×1.139) kcal/mol	Sordo 2001, Chan 2004
0.001	2202.3	[C2]- (g) → 2 C (g)	Δ_rH°(0 K) = 219.94 ± 1.72 kcal/mol	Ruscic G3X
0.001	2198.12	[C2]- (g) → C2 (g)	Δ_rH°(0 K) = 3.214 ± 0.090 eV	Ruscic CBS-n

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. 1.130 of the Thermochemical Network. Argonne National Laboratory, Lemont, Illinois 2023; available at ATcT.anl.gov [DOI: 10.17038/CSE/1997229]
4		N. Genossar, P. B. Changala, B. Gans, J.-C. Loison, S. Hartweg, M.-A. Martin-Drumel, G. A. Garcia, J. F. Stanton, B. Ruscic, and J. H. Baraban Ring-Opening Dynamics of the Cyclopropyl Radical and Cation: the Transition State Nature of the Cyclopropyl Cation J. Am. Chem. Soc. 144, 18518-18525 (2022) [DOI: 10.1021/jacs.2c07740]
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		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]
8		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]).
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.