Selected ATcT [1, 2] enthalpy of formation based on version 1.156 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.148 to include species relevant to a recent study of the oxidation of ethylene [4] as well as new measurements that led to refining the thermochemistry of CF and SiF and their cations [5].

Disulfur

Formula: S2 (g)

CAS RN: 23550-45-0

ATcT ID: 23550-45-0*0

SMILES: S=S

InChI: InChI=1S/S2/c1-2

InChIKey: MAHNFPMIPQKPPI-UHFFFAOYSA-N

Hills Formula: S2

2D Image:

Aliases: S2; Disulfur; Sulfur dimer; Diatomic sulfur; Sulfur

Relative Molecular Mass: 64.1320 ± 0.0120

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
127.37	127.68	± 0.27	kJ/mol

3D Image of S2 (g)

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Top contributors to the provenance of Δ_fH° of S2 (g)

The 10 contributors listed below account for 91.5% of the provenance of Δ_fH° of S2 (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
30.0	9168.1	S (cr,l) + O2 (g) → OSO (g)	Δ_rH°(298.15 K) = -296.847 ± 0.200 kJ/mol	Eckman 1929, note SO2
16.0	9298.1	S (cr,l) + 3/2 O2 (g) + H2O (cr,l) → OS(O)(OH)2 (aq, 115 H2O)	Δ_rH°(298.15 K) = -143.85 ± 0.06 kcal/mol	Good 1960, CODATA Key Vals
11.8	9298.2	S (cr,l) + 3/2 O2 (g) + H2O (cr,l) → OS(O)(OH)2 (aq, 115 H2O)	Δ_rH°(298.15 K) = -143.92 ± 0.07 kcal/mol	Mansson 1963, CODATA Key Vals
11.1	9188.1	SO (g) → S (g) + O (g)	Δ_rH°(0 K) = 43275 ± 5 cm-1	Clerbaux 1994
5.6	9153.2	2 S (cr,l) → S2 (g)	Δ_rG°(570 K) = 9.483 ± 0.138 (×1.915) kcal/mol	Drowart 1968, Detry 1967, 3rd Law
4.7	9337.1	S (cr,l) + 3/2 O2 (g) + H2O (cr,l) → OS(O)(OH)2 (aq, 45 H2O)	Δ_rH°(298.15 K) = -143.67 ± 0.11 kcal/mol	McCullough 1957a
4.2	9153.4	2 S (cr,l) → S2 (g)	Δ_rG°(600 K) = 8.57 ± 0.29 (×1.044) kcal/mol	Braune 1951, West 1929, Gurvich TPIS, 3rd Law
3.2	9297.1	S (cr,l) + 3/2 O2 (g) + H2O (cr,l) → OS(O)(OH)2 (aq, 70 H2O)	Δ_rH°(298.15 K) = -143.58 ± 0.09 (×1.477) kcal/mol	McCullough 1953, CODATA Key Vals
2.2	9298.3	S (cr,l) + 3/2 O2 (g) + H2O (cr,l) → OS(O)(OH)2 (aq, 115 H2O)	Δ_rH°(298.15 K) = -143.70 ± 0.07 (×2.278) kcal/mol	Waddington 1956, Mansson 1963, est unc
2.2	9296.1	OSO (g) + 1/2 O2 (g) + H2O (cr,l) → OS(O)(OH)2 (cr,l)	Δ_rH°(298.15 K) = -231.329 ± 0.040 kJ/mol	NBS Tables 1989

Top 10 species with enthalpies of formation correlated to the Δ_fH° of S2 (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
99.3	Sulfur	S (g)	276.83	279.08	± 0.14	kJ/mol	32.0660 ± 0.0060	7704-34-9*0
99.3	Monosulfur anion	S- (g)	76.42	78.48	± 0.14	kJ/mol	32.0665 ± 0.0060	14337-03-2*0
99.1	Monosulfur cation	S+ (g)	1276.42	1278.21	± 0.14	kJ/mol	32.0655 ± 0.0060	14701-12-3*0
97.5	Sulfur atom dication	[S]+2 (g)	3528.18	3531.88	± 0.14	kJ/mol	32.0649 ± 0.0060	14127-58-3*0
90.0	Sulfur monoxide	SO (g)	5.95	6.00	± 0.13	kJ/mol	48.0654 ± 0.0060	13827-32-2*0
90.0	Sulfur dioxide	OSO (g)	-294.20	-296.74	± 0.13	kJ/mol	64.0648 ± 0.0060	7446-09-5*0
88.8	Oxosulfur	[SO]+ (g)	999.26	999.87	± 0.13	kJ/mol	48.0649 ± 0.0060	767269-11-4*0
88.4	Sulfonyl cation	[OSO]+ (g)	897.01	894.74	± 0.13	kJ/mol	64.0643 ± 0.0060	12439-77-9*0
84.0	Sulfuric acid	OS(O)(OH)2 (cr,l)	-811.88	-813.87	± 0.13	kJ/mol	98.0795 ± 0.0061	7664-93-9*500
83.5	Sulfur dioxide	OSO (aq, undissoc)		-320.69	± 0.14	kJ/mol	64.0648 ± 0.0060	7446-09-5*1000

Most Influential reactions involving S2 (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
0.971	9147.1	S2 (g) → 2 S (g)	Δ_rH°(0 K) = 35636.3 ± 2.5 cm-1	Ricks 1969, Huber 1979, Green 1997, Frederix 2009
0.921	9149.1	S2 (g) → [S2]+ (g)	Δ_rH°(0 K) = 75580 ± 16 cm-1	Hrodmarsson 2021
0.854	9150.11	[S2]- (g) → S2 (g)	Δ_rH°(0 K) = 1.673 ± 0.005 eV	Feller 2016a, Feller 2016, est unc
0.244	9569.7	SCS (g) → C (g) + S2 (g)	Δ_rH°(0 K) = 172.97 ± 0.30 kcal/mol	Karton 2011
0.121	9247.8	OSO (g) + 3/2 S2 (g) → 2 SSO (g)	Δ_rH°(0 K) = -0.01 ± 0.40 (×1.164) kcal/mol	Karton 2011
0.094	9150.1	[S2]- (g) → S2 (g)	Δ_rH°(0 K) = 1.670 ± 0.015 eV	Moran 1988
0.070	9569.6	SCS (g) → C (g) + S2 (g)	Δ_rH°(0 K) = 172.84 ± 0.56 kcal/mol	Karton 2011
0.069	9161.11	S2 (g) + 2 H2O (g) → O2 (g) + 2 H2S (g)	Δ_rH°(0 K) = 75.51 ± 0.25 kcal/mol	Feller 2008
0.069	9161.10	S2 (g) + 2 H2O (g) → O2 (g) + 2 H2S (g)	Δ_rH°(0 K) = 75.40 ± 0.25 kcal/mol	Karton 2006, Karton 2011
0.065	9247.9	OSO (g) + 3/2 S2 (g) → 2 SSO (g)	Δ_rH°(0 K) = -0.17 ± 0.25 (×2.538) kcal/mol	Karton 2006, Karton 2011
0.059	9246.10	SSO (g) → S2 (g) + O (g)	Δ_rH°(0 K) = 101.87 ± 0.30 (×1.114) kcal/mol	Karton 2006
0.056	9153.2	2 S (cr,l) → S2 (g)	Δ_rG°(570 K) = 9.483 ± 0.138 (×1.915) kcal/mol	Drowart 1968, Detry 1967, 3rd Law
0.042	9153.4	2 S (cr,l) → S2 (g)	Δ_rG°(600 K) = 8.57 ± 0.29 (×1.044) kcal/mol	Braune 1951, West 1929, Gurvich TPIS, 3rd Law
0.040	9568.1	SCS (g) → C (graphite) + S2 (g)	Δ_rG°(1235 K) = 19.6 ± 3.1 kJ/mol	Koref 1910, 3rd Law
0.040	9155.4	S2 (g) + 2 H2 (g) → 2 H2S (g)	Δ_rG°(1515 K) = -31.42 ± 0.80 (×1.719) kJ/mol	Randall 1918, Gurvich TPIS, 2nd Law
0.036	9247.7	OSO (g) + 3/2 S2 (g) → 2 SSO (g)	Δ_rH°(0 K) = 0.90 ± 0.85 kcal/mol	Karton 2011
0.036	9149.4	S2 (g) → [S2]+ (g)	Δ_rH°(0 K) = 9.38 ± 0.01 eV	Dyke 1975
0.032	9247.6	OSO (g) + 3/2 S2 (g) → 2 SSO (g)	Δ_rH°(0 K) = 0.89 ± 0.90 kcal/mol	Ruscic W1RO
0.026	9161.9	S2 (g) + 2 H2O (g) → O2 (g) + 2 H2S (g)	Δ_rH°(0 K) = 75.57 ± 0.40 kcal/mol	Karton 2011
0.026	9247.4	OSO (g) + 3/2 S2 (g) → 2 SSO (g)	Δ_rH°(0 K) = -0.01 ± 1.00 kcal/mol	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. 1.156 of the Thermochemical Network (2024); available at ATcT.anl.gov
4		N. A. Seifert, B. Ruscic, R. Sivaramakrishnan, and K. Prozument, The C2H4O Isomers in the Oxidation of Ethylene J. Mol. Spectrosc. 398, 111847/1-8 (2023) [DOI: 10.1016/j.jms.2023.111847]
5		U. Jacovella, B. Ruscic, N. L. Chen, H.-L. Le, S. Boyé-Péronne, S. Hartweg, M. Roy-Chowdhury, G. A. Garcia, J.-C. Loison, and B. Gans, Refining Thermochemical Properties of CF, SiF, and Their Cations by Combining Photoelectron Spectroscopy, Quantum Chemical Calculations, and the Active Thermochemical Tables Approach Phys. Chem. Chem. Phys. 25, 30838-30847 (2023) [DOI: 10.1039/D3CP04244H]
6		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]
7		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] and Ruscic and Bross[7]).
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.