Selected ATcT [1, 2] enthalpy of formation based on version 1.176 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.172 to include species related to Criegee intermediates that are involved in several ongoing studies[4].

Acetylene

Formula: HCCH (g)
CAS RN: 74-86-2
ATcT ID: 74-86-2*0
SMILES: C#C
InChI: InChI=1S/C2H2/c1-2/h1-2H
InChIKey: HSFWRNGVRCDJHI-UHFFFAOYSA-N
Hills Formula: C2H2

2D Image:

C#C
Aliases: HCCH; Acetylene; Ethyne; Narcylen; Vinylene; CHCH
Relative Molecular Mass: 26.0373 ± 0.0016

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
228.86228.30± 0.12kJ/mol

3D Image of HCCH (g)

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Top contributors to the provenance of ΔfH° of HCCH (g)

The 20 contributors listed below account only for 26.9% of the provenance of ΔfH° of HCCH (g).
A total of 733 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
2.92375.1 H2 (g) C (graphite) → CH4 (g) ΔrG°(1165 K) = 37.521 ± 0.068 kJ/molSmith 1946, note COf, 3rd Law
2.52268.11 CO (g) → C (g) O (g) ΔrH°(0 K) = 1071.92 ± 0.10 kJ/molThorpe 2021
1.82286.9 C (graphite) CO2 (g) → 2 CO (g) ΔrG°(1165 K) = -33.545 ± 0.058 kJ/molSmith 1946, note COf, 3rd Law
1.62596.7 HCCH (g) → 2 C (g) + 2 H (g) ΔrH°(0 K) = 1626.04 ± 0.56 kJ/molHarding 2008
1.32595.13 HCCH (g) → 2 C (g) + 2 H (g) ΔrH°(0 K) = 388.71 ± 0.15 kcal/molKarton 2007a
1.32310.7 HCCH (g) → 2 H (g) C2 (g) ΔrH°(0 K) = 244.65 ± 0.15 kcal/molKarton 2007a
1.3125.2 1/2 O2 (g) H2 (g) → H2O (cr,l) ΔrH°(298.15 K) = -285.8261 ± 0.040 kJ/molRossini 1939, Rossini 1931, Rossini 1931b, note H2Oa, Rossini 1930
1.22278.2 CO (g) → C+ (g) O (g) ΔrH°(0 K) = 22.3713 ± 0.0015 eVNg 2007
1.12614.2 CH2CH2 (g) → [HCCH]+ (g) H2 (g) ΔrH°(0 K) = 13.135 ± 0.005 (×1.354) eVMahnert 1996
1.12614.1 CH2CH2 (g) → [HCCH]+ (g) H2 (g) ΔrH°(0 K) = 13.135 ± 0.005 (×1.354) eVMalow 1999, est unc
1.12228.7 C (graphite) O2 (g) → CO2 (g) ΔrH°(298.15 K) = -393.464 ± 0.024 kJ/molHawtin 1966, note CO2e
1.02596.5 HCCH (g) → 2 C (g) + 2 H (g) ΔrH°(0 K) = 1626.04 ± 0.70 kJ/molHarding 2008, Ferguson 2013
1.02596.4 HCCH (g) → 2 C (g) + 2 H (g) ΔrH°(0 K) = 1626.21 ± 0.70 kJ/molBomble 2006
1.02596.11 HCCH (g) → 2 C (g) + 2 H (g) ΔrH°(0 K) = 1626.15 ± 0.70 kJ/molHarding 2007
1.02612.6 HCCH (g) H2 (g) → CH2CH2 (g) ΔrH°(0 K) = -167.71 ± 0.70 kJ/molHarding 2007
1.02529.1 CH2CH2 (g) + 3 O2 (g) → 2 CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -1411.18 ± 0.30 kJ/molRossini 1937
0.92596.6 HCCH (g) → 2 C (g) + 2 H (g) ΔrH°(0 K) = 1625.72 ± 0.74 kJ/molHarding 2008
0.92611.11 HCCH (g) + 2 H2 (g) → CH3CH3 (g) ΔrH°(0 K) = -71.01 ± 0.20 kcal/molKarton 2007
0.92596.3 HCCH (g) → 2 C (g) + 2 H (g) ΔrH°(0 K) = 1625.88 ± 0.75 kJ/molBomble 2006
0.92596.1 HCCH (g) → 2 C (g) + 2 H (g) ΔrH°(0 K) = 1626.06 ± 0.75 kJ/molTajti 2004, est unc

Top 10 species with enthalpies of formation correlated to the ΔfH° of HCCH (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
100.0 Acetylene cation[HCCH]+ (g)C#[CH+]1328.881328.21± 0.12kJ/mol26.0367 ±
0.0016
25641-79-6*0
78.7 Ethynylium[CCH]+ (g)C#[C+]1687.621690.95± 0.15kJ/mol25.0288 ±
0.0016
16456-59-0*0
64.5 EthynylCCH (g)C#[C]563.73567.85± 0.15kJ/mol25.0293 ±
0.0016
2122-48-7*0
55.5 Carbon cationC+ (g)[C+]1797.8341803.432± 0.039kJ/mol12.01015 ±
0.00080
14067-05-1*0
55.5 CarbonC (g, triplet)[C]711.381716.866± 0.039kJ/mol12.01070 ±
0.00080
7440-44-0*1
55.5 CarbonC (g)[C]711.381716.866± 0.039kJ/mol12.01070 ±
0.00080
7440-44-0*0
55.5 CarbonC (g, singlet)[C]833.312838.459± 0.039kJ/mol12.01070 ±
0.00080
7440-44-0*2
55.5 CarbonC (g, quintuplet)[C]1114.9441120.091± 0.039kJ/mol12.01070 ±
0.00080
7440-44-0*3
55.4 Carbon dication[C]+2 (g)[C++]4150.4514155.597± 0.039kJ/mol12.00960 ±
0.00080
16092-61-8*0
55.2 Carbon anionC- (g)[C-]589.605594.751± 0.039kJ/mol12.01125 ±
0.00080
14337-00-9*0

Most Influential reactions involving HCCH (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
0.9802598.1 HCCH (g) → [HCCH]+ (g) ΔrH°(0 K) = 91953.77 ± 0.06 cm-1Tang 2006
0.8722653.5 HCCH (g) → [CCH]+ (g) H (g) ΔrH°(0 K) = 17.3576 ± 0.0010 eVJarvis 1999, Weitzel 2001
0.5987603.1 CHICHI (g, trans) → HCCH (g) I2 (g) ΔrG°(600 K) = 1.26 ± 0.10 kcal/molFuruyama 1968
0.5987602.1 CHICHI (g, cis) → HCCH (g) I2 (g) ΔrG°(600 K) = 0.60 ± 0.10 kcal/molFuruyama 1968
0.3946230.8 HCCH (g) ClCCCl (g) → 2 HCCCl (g) ΔrH°(0 K) = -0.76 ± 0.25 kcal/molKarton 2017, Karton 2011, Karton 2007, Karton 2006
0.3912856.6 HCCNH (g) CH4 (g) → CH3NH (g) HCCH (g) ΔrH°(0 K) = 87.84 ± 1.5 kJ/molKlippenstein 2017
0.3476678.12 HCCH (g) FCCF (g) → 2 HCCF (g) ΔrH°(0 K) = -5.22 ± 0.20 kcal/molKarton 2011
0.3276838.6 HCCH (g) → HCCCCCCH (g) + 2 H2 (g) ΔrH°(0 K) = -2.60 ± 2.00 kJ/molKlippenstein 2017
0.3255365.6 HOCCOH (g) HCCH (g) → 2 HCCOH (g, singlet) ΔrH°(0 K) = -20.17 ± 2.00 kJ/molKlippenstein 2017
0.2936696.4 HCCH (g) BrCCBr (g) → 2 HCCBr (g) ΔrH°(0 K) = 0.45 ± 1.0 kcal/molRuscic G4
0.2806674.2 HCCH (g) + 2 CH3Br (g) → BrCCBr (g) + 2 CH4 (g) ΔrH°(0 K) = 2.34 ± 1.0 kcal/molRuscic G4
0.2746837.6 HCCCCCCH (g) HCCH (g) → 2 HCCCCH (g) ΔrH°(0 K) = 5.15 ± 2.00 kJ/molKlippenstein 2017
0.2632608.6 HCCH (g) → HCCH (g, cis-triplet) ΔrH°(0 K) = 30900 ± 230 cm-1Sherrill 2000
0.2586848.4 HCCCCCCH (g) CCH (g) → CCCCCCH (g) HCCH (g) ΔrH°(0 K) = -3.84 ± 0.90 kcal/molRuscic CBS-n
0.2426696.3 HCCH (g) BrCCBr (g) → 2 HCCBr (g) ΔrH°(0 K) = 0.65 ± 1.1 kcal/molRuscic G3X
0.2316674.1 HCCH (g) + 2 CH3Br (g) → BrCCBr (g) + 2 CH4 (g) ΔrH°(0 K) = 3.37 ± 1.1 kcal/molRuscic G3X
0.2186679.12 HCCH (g) CH3F (g) → HCCF (g) CH4 (g) ΔrH°(0 K) = 8.81 ± 0.20 kcal/molKarton 2011
0.2163687.14 C (g) HCCH (g) → CH(CC) (g) H (g) ΔrH°(0 K) = -12.15 ± 1.5 kJ/molKlippenstein 2017
0.2133490.5 CH3CHC (g, triplet) HCCH (g) → CCH2 (g, triplet) CH3CCH (g) ΔrH°(0 K) = -13.16 ± 0.85 kcal/molRuscic W1RO
0.2076229.1 HCCCl (g) CH2CH2 (g) → CH2CHCl (g) HCCH (g) ΔrH°(0 K) = -7.80 ± 0.25 kcal/molKarton 2017, Karton 2011, Karton 2007, Karton 2006


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. 1.176 of the Thermochemical Network (2024); available at ATcT.anl.gov
4   T. L. Nguyen et al, ongoing studies (2024)
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.