Selected ATcT [1, 2] enthalpy of formation based on version 1.148 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.140 to include species relevant to a recent study of the role of atmospheric methanediol[4].

Propynylidene

Formula: HCCCH (g, singlet)

CAS RN: 67152-18-5

ATcT ID: 67152-18-5*2

SMILES: [CH]=C=[CH]

SMILES: C#C[CH]

InChI: InChI=1S/C3H2/c1-3-2/h1-2H

InChIKey: OUSWHEMIRJJMAW-UHFFFAOYSA-N

Hills Formula: C3H2

2D Image:

Aliases: HCCCH; Propynylidene; 1,2-Propadiene-1,3-diyl; CHCCH; HC=C=CH; CH=C=CH; 2008-19-7; Propargylene; Propargylene radical; 2-Propynylidene; 2-Propyn-1-ylidene; HC-C~CH; HC~C-CH; CH-C~CH; CH~C-CH

Relative Molecular Mass: 38.0480 ± 0.0024

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
597.9	599.6	± 1.2	kJ/mol

3D Image of HCCCH (g, singlet)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of HCCCH (g, singlet)

The 20 contributors listed below account only for 77.2% of the provenance of Δ_fH° of HCCCH (g, singlet).
A total of 61 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
6.1	3513.7	HCCCH (g, triplet) → HCCCH (g, cis singlet)	Δ_rH°(0 K) = 53.81 ± 4 kJ/mol	Aguilera-Iparraguirre 2008, est unc
5.7	3521.1	[HCCCH]- (g, transoid 2B) + HCCCH (g, triplet) → [HCCCH]- (g, cisoid 2A) + HCCCH (g, trans singlet)	Δ_rH°(0 K) = 0.583 ± 0.010 eV	Osborn 2014
5.0	3539.5	HCCCH (g, cis singlet) → CH2CC (g)	Δ_rH°(0 K) = -10.53 ± 1.2 kcal/mol	Ruscic W1RO
4.4	3520.4	[HCCCH]- (g, transoid 2B) + HCCCH (g, cis singlet) → HCCCH (g, trans singlet) + [HCCCH]- (g, cisoid 2A)	Δ_rH°(0 K) = 227 ± 300 cm-1	Ruscic W1RO
4.3	3539.2	HCCCH (g, cis singlet) → CH2CC (g)	Δ_rH°(0 K) = -10.43 ± 1.3 kcal/mol	Ruscic G4
4.1	3520.2	[HCCCH]- (g, transoid 2B) + HCCCH (g, cis singlet) → HCCCH (g, trans singlet) + [HCCCH]- (g, cisoid 2A)	Δ_rH°(0 K) = 220 ± 310 cm-1	Ruscic G4
4.1	3500.5	[HCCCH]- (g, cisoid 2A) → HCCCH (g, cis singlet)	Δ_rH°(0 K) = 1.681 ± 0.050 eV	Ruscic W1RO
4.0	3520.1	[HCCCH]- (g, transoid 2B) + HCCCH (g, cis singlet) → HCCCH (g, trans singlet) + [HCCCH]- (g, cisoid 2A)	Δ_rH°(0 K) = 221 ± 315 cm-1	Ruscic G3X
3.9	3515.4	HCCCH (g, cis singlet) → HCCCH (g, trans singlet)	Δ_rH°(0 K) = 1 ± 300 cm-1	Ruscic W1RO
3.8	3513.5	HCCCH (g, triplet) → HCCCH (g, cis singlet)	Δ_rH°(0 K) = 4924 ± 420 cm-1	Ruscic W1RO
3.7	3539.1	HCCCH (g, cis singlet) → CH2CC (g)	Δ_rH°(0 K) = -10.49 ± 1.4 kcal/mol	Ruscic G3X
3.7	3515.2	HCCCH (g, cis singlet) → HCCCH (g, trans singlet)	Δ_rH°(0 K) = 35 ± 310 cm-1	Ruscic G4
3.6	3515.1	HCCCH (g, cis singlet) → HCCCH (g, trans singlet)	Δ_rH°(0 K) = 6 ± 315 cm-1	Ruscic G3X
3.3	3513.2	HCCCH (g, triplet) → HCCCH (g, cis singlet)	Δ_rH°(0 K) = 4156 ± 450 cm-1	Ruscic G4
3.2	3520.3	[HCCCH]- (g, transoid 2B) + HCCCH (g, cis singlet) → HCCCH (g, trans singlet) + [HCCCH]- (g, cisoid 2A)	Δ_rH°(0 K) = 220 ± 350 cm-1	Ruscic CBS-n
2.9	3515.3	HCCCH (g, cis singlet) → HCCCH (g, trans singlet)	Δ_rH°(0 K) = 5 ± 350 cm-1	Ruscic CBS-n
2.8	3539.3	HCCCH (g, cis singlet) → CH2CC (g)	Δ_rH°(0 K) = -10.95 ± 1.6 kcal/mol	Ruscic CBS-n
2.8	3513.1	HCCCH (g, triplet) → HCCCH (g, cis singlet)	Δ_rH°(0 K) = 4287 ± 490 cm-1	Ruscic G3X
2.7	3500.2	[HCCCH]- (g, cisoid 2A) → HCCCH (g, cis singlet)	Δ_rH°(0 K) = 1.678 ± 0.061 eV	Ruscic G4
2.1	3513.3	HCCCH (g, triplet) → HCCCH (g, cis singlet)	Δ_rH°(0 K) = 4967 ± 560 cm-1	Ruscic CBS-n

Top 10 species with enthalpies of formation correlated to the Δ_fH° of HCCCH (g, singlet)

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
100.0	Propynylidene	HCCCH (g, cis singlet)	597.9	599.6	± 1.2	kJ/mol	38.0480 ± 0.0024	67152-18-5*3
44.6	Propynylidene	HCCCH (g, trans singlet)	597.6	599.4	± 1.1	kJ/mol	38.0480 ± 0.0024	67152-18-5*4
36.2	Propynylidene	HCCCH (g, triplet)	543.73	546.73	± 0.58	kJ/mol	38.0480 ± 0.0024	67152-18-5*1
36.2	Propynylidene	HCCCH (g)	543.73	546.73	± 0.58	kJ/mol	38.0480 ± 0.0024	67152-18-5*0
24.1	Propargylenide	[HCCCH]- (g)	434.5	437.7	± 1.1	kJ/mol	38.0485 ± 0.0024	82906-05-6*0
24.1	Propargylenide	[HCCCH]- (g, transoid 2B)	434.5	437.0	± 1.1	kJ/mol	38.0485 ± 0.0024	82906-05-6*1
23.4	Propynylidene cation	[HCCCH]+ (g)	1409.62	1412.17	± 0.83	kJ/mol	38.0474 ± 0.0024	75123-91-0*0
20.7	Propargylenide	[HCCCH]- (g, cisoid 2A)	437.0	439.5	± 1.1	kJ/mol	38.0485 ± 0.0024	82906-05-6*2
16.9	Propadienylidene	CH2CC (g)	554.46	555.61	± 0.40	kJ/mol	38.0480 ± 0.0024	60731-10-4*0
16.5	Propadienylidenide	[CH2CC]- (g)	381.19	382.10	± 0.41	kJ/mol	38.0485 ± 0.0024	109292-49-1*0

Most Influential reactions involving HCCCH (g, singlet)

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
1.000	3512.1	HCCCH (g, singlet) → HCCCH (g, cis singlet)	Δ_rH°(0 K) = 0.00 ± 0.00 cm-1	Ruscic W1RO, Ruscic G4

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. 1.148 of the Thermochemical Network (2023); available at ATcT.anl.gov
4		T. L. Nguyen, J. Peeters, J.-F. Müller, A. Perera, D. H. Bross, B. Ruscic, and J. F. Stanton, Methanediol from Cloud-Processed Formaldehyde is Only a Minor Source of Atmospheric Formic Acid Natl. Acad. Sci. 120, e2304650120/1-8 (2023) [DOI: 10.1073/pnas.2304650120]
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.