Selected ATcT [1, 2] enthalpy of formation based on version 1.140 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.130 to fully include the highest-level electronic structure computations described in reference [4].

1-Ethenylium-1-yl

Formula: [CCH2]+ (g)

CAS RN: 80541-07-7

ATcT ID: 80541-07-7*0

SMILES: [C+]=C

InChI: InChI=1S/C2H2/c1-2/h1H2/q+1

InChIKey: PIDCOQBXPFWHKL-UHFFFAOYSA-N

Hills Formula: C2H2+

2D Image:

Aliases: [CCH2]+; 1-Ethenylium-1-yl; 1-Ethenylium-1-yl ion; 1-Ethenylium-1-yl cation; 1-Ethenylium-1-yl ion (1+); Vinylidene cation; Vinylidene ion (1+); Ethenylidene cation; Ethenylidene ion (1+); Methylenecarbene cation; Methylenecarbene ion (1+); Methylidenecarbene cation; Methylidenecarbene ion (1+); CCH2+; [CH2C]+; CH2C+; [H2CC]+; H2CC+

Relative Molecular Mass: 26.0367 ± 0.0016

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
1507.1	1507.1	± 2.1	kJ/mol

3D Image of [CCH2]+ (g)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of [CCH2]+ (g)

The 9 contributors listed below account for 94.6% of the provenance of Δ_fH° of [CCH2]+ (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
28.5	2527.8	CCH2 (g) → [CCH2]+ (g)	Δ_rH°(0 K) = 11.343 ± 0.040 eV	Ruscic W1RO
11.0	2529.8	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 83.35 ± 1.50 kcal/mol	Ruscic W1RO
9.6	2529.7	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 82.90 ± 1.60 kcal/mol	Ruscic CBS-n
9.6	2529.4	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 83.01 ± 1.60 kcal/mol	Ruscic G4
8.5	2527.4	CCH2 (g) → [CCH2]+ (g)	Δ_rH°(0 K) = 11.375 ± 0.073 eV	Ruscic G4
8.3	2529.3	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 83.21 ± 1.72 kcal/mol	Ruscic G3X
8.1	2527.7	CCH2 (g) → [CCH2]+ (g)	Δ_rH°(0 K) = 11.323 ± 0.075 eV	Ruscic CBS-n
5.3	2529.6	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 81.36 ± 2.16 kcal/mol	Ruscic CBS-n
5.2	2527.3	CCH2 (g) → [CCH2]+ (g)	Δ_rH°(0 K) = 11.370 ± 0.093 eV	Ruscic G3X

Top 10 species with enthalpies of formation correlated to the Δ_fH° of [CCH2]+ (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
8.2	Vinylidene	CCH2 (g)	411.21	412.12	± 0.30	kJ/mol	26.0373 ± 0.0016	2143-69-3*0
8.0	Vinylidene anion	[CCH2]- (g)	364.25	364.06	± 0.31	kJ/mol	26.0378 ± 0.0016	66295-36-1*0
6.1	Vinylidene	CCH2 (g, triplet)	610.62	610.33	± 0.39	kJ/mol	26.0373 ± 0.0016	2143-69-3*1
3.4	Carbon dication	[C]+2 (g)	4150.459	4155.605	± 0.040	kJ/mol	12.00960 ± 0.00080	16092-61-8*0
3.4	Carbon cation	C+ (g)	1797.842	1803.440	± 0.040	kJ/mol	12.01015 ± 0.00080	14067-05-1*0
3.4	Carbon	C (g, singlet)	833.320	838.467	± 0.040	kJ/mol	12.01070 ± 0.00080	7440-44-0*2
3.4	Carbon	C (g, quintuplet)	1114.952	1120.099	± 0.040	kJ/mol	12.01070 ± 0.00080	7440-44-0*3
3.4	Carbon	C (g, triplet)	711.389	716.874	± 0.040	kJ/mol	12.01070 ± 0.00080	7440-44-0*1
3.4	Carbon	C (g)	711.389	716.874	± 0.040	kJ/mol	12.01070 ± 0.00080	7440-44-0*0
3.4	Carbon anion	C- (g)	589.613	594.759	± 0.040	kJ/mol	12.01125 ± 0.00080	14337-00-9*0

Most Influential reactions involving [CCH2]+ (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
0.291	2527.8	CCH2 (g) → [CCH2]+ (g)	Δ_rH°(0 K) = 11.343 ± 0.040 eV	Ruscic W1RO
0.110	2529.8	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 83.35 ± 1.50 kcal/mol	Ruscic W1RO
0.097	2529.4	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 83.01 ± 1.60 kcal/mol	Ruscic G4
0.097	2529.7	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 82.90 ± 1.60 kcal/mol	Ruscic CBS-n
0.087	2527.4	CCH2 (g) → [CCH2]+ (g)	Δ_rH°(0 K) = 11.375 ± 0.073 eV	Ruscic G4
0.084	2529.3	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 83.21 ± 1.72 kcal/mol	Ruscic G3X
0.082	2527.7	CCH2 (g) → [CCH2]+ (g)	Δ_rH°(0 K) = 11.323 ± 0.075 eV	Ruscic CBS-n
0.053	2527.3	CCH2 (g) → [CCH2]+ (g)	Δ_rH°(0 K) = 11.370 ± 0.093 eV	Ruscic G3X
0.053	2529.6	[CCH2]+ (g) → 2 C (g) + 2 H (g)	Δ_rH°(0 K) = 81.36 ± 2.16 kcal/mol	Ruscic CBS-n
0.047	2527.6	CCH2 (g) → [CCH2]+ (g)	Δ_rH°(0 K) = 11.375 ± 0.099 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. 1.140 of the Thermochemical Network (2024); available at ATcT.anl.gov
4		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]
5		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]
6		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 [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.

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.