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].

Ethynylamidogen anion

Formula: [HCCNH]- (g)

CAS RN: 64066-03-1

ATcT ID: 64066-03-1*0

SMILES: C#C[NH-]

InChI: InChI=1S/C2H2N/c1-2-3/h1,3H/q-1

InChIKey: BSTKTQGGUXZGPC-UHFFFAOYSA-N

Hills Formula: C2H2N1-

2D Image:

Aliases: [HCCNH]-; Ethynylamidogen anion; Ethynylamidogen ion (1-); HCCNH-; 87351-74-4; Iminoethenyl anion; Iminoethenyl ion (1-)

Relative Molecular Mass: 40.0446 ± 0.0016

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
233.7	230.5	± 3.2	kJ/mol

3D Image of [HCCNH]- (g)

spin ON spin OFF

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

The 5 contributors listed below account for 90.7% of the provenance of Δ_fH° of [HCCNH]- (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
34.6	2761.5	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.680 ± 0.050 eV	Ruscic W1RO
23.2	2761.2	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.684 ± 0.061 eV	Ruscic G4
11.9	2761.1	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.667 ± 0.085 eV	Ruscic G3X
10.6	2761.4	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.665 ± 0.090 eV	Ruscic CBS-n
10.2	2761.3	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.655 ± 0.092 eV	Ruscic CBS-n

Top 10 species with enthalpies of formation correlated to the Δ_fH° of [HCCNH]- (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
30.4	Ethynylamidogen	HCCNH (g)	395.26	393.23	± 0.96	kJ/mol	40.0440 ± 0.0016	73456-14-1*0
11.6	Ethynylaminylium	[HCCNH]+ (g, singlet)	1350.6	1348.7	± 2.5	kJ/mol	40.0435 ± 0.0016	103835-08-1*2
11.2	Ethynylaminylium	[HCCNH]+ (g, triplet)	1277.8	1277.4	± 2.6	kJ/mol	40.0435 ± 0.0016	103835-08-1*1
11.2	Ethynylaminylium	[HCCNH]+ (g)	1277.8	1277.4	± 2.6	kJ/mol	40.0435 ± 0.0016	103835-08-1*0
8.6	Cyanomethyl	CH2CN (g)	262.84	259.96	± 0.53	kJ/mol	40.0440 ± 0.0016	2932-82-3*0
8.6	Cyanomethanide	[CH2CN]- (g)	113.69	110.87	± 0.53	kJ/mol	40.0446 ± 0.0016	21438-99-3*0
7.6	Cyanomethylium	[CH2CN]+ (g)	1256.23	1253.59	± 0.61	kJ/mol	40.0435 ± 0.0016	34430-18-7*0
7.2	Methylamidogen	CH3NH (g)	187.90	177.24	± 0.40	kJ/mol	30.04920 ± 0.00085	15622-51-2*0
3.0	Methylamine	CH3NH2 (g)	-6.54	-21.24	± 0.22	kJ/mol	31.05714 ± 0.00088	74-89-5*0
2.6	Methylammoniumyl	[CH3NH2]+ (g)	865.90	851.96	± 0.25	kJ/mol	31.05659 ± 0.00088	34516-31-9*0

Most Influential reactions involving [HCCNH]- (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
0.381	2761.5	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.680 ± 0.050 eV	Ruscic W1RO
0.256	2761.2	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.684 ± 0.061 eV	Ruscic G4
0.132	2761.1	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.667 ± 0.085 eV	Ruscic G3X
0.117	2761.4	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.665 ± 0.090 eV	Ruscic CBS-n
0.112	2761.3	[HCCNH]- (g) → HCCNH (g)	Δ_rH°(0 K) = 1.655 ± 0.092 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.