Selected ATcT [1, 2] enthalpy of formation based on version 1.172 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.156 to include species relevant to a study of photodissociation of formamide[4].

Hypochlorous acid

Formula: HOCl (aq, undissoc)

CAS RN: 7790-92-3

ATcT ID: 7790-92-3*1000

SMILES: OCl

InChI: InChI=1S/ClHO/c1-2/h2H

InChIKey: QWPPOHNGKGFGJK-UHFFFAOYSA-N

Hills Formula: Cl1H1O1

2D Image:

Aliases: Hypochlorous acid; Hydrogen oxychloride; Pure Star MP 100000C; Chlorine hydroxide; Hydroxyl chloride; Hydroxychlorine; Hydroxidochlorine; ClOH; HOCl

Relative Molecular Mass: 52.46004 ± 0.00095

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
	-125.526	± 0.050	kJ/mol

Top contributors to the provenance of Δ_fH° of HOCl (aq, undissoc)

The 9 contributors listed below account for 90.0% of the provenance of Δ_fH° of HOCl (aq, undissoc).

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
78.3	1052.1	HOCl (g) → HOCl (aq, undissoc)	Δ_rG°(298.15 K) = -16.067 ± 0.045 kJ/mol	Huthwelker 1995, Sander 2023, note unc
5.5	125.2	1/2 O2 (g) + H2 (g) → H2O (cr,l)	Δ_rH°(298.15 K) = -285.8261 ± 0.040 kJ/mol	Rossini 1939, Rossini 1931, Rossini 1931b, note H2Oa, Rossini 1930
1.6	2373.7	CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l)	Δ_rH°(298.15 K) = -890.578 ± 0.078 kJ/mol	Schley 2010
1.4	2375.1	2 H2 (g) + C (graphite) → CH4 (g)	Δ_rG°(1165 K) = 37.521 ± 0.068 kJ/mol	Smith 1946, note COf, 3rd Law
1.3	1040.1	HOCl (g) → OH (g) + Cl (g)	Δ_rH°(0 K) = 19287.9 ± 0.7 cm-1	Barnes 1997
0.5	1040.2	HOCl (g) → OH (g) + Cl (g)	Δ_rH°(0 K) = 19289.4 ± 0.7 (×1.61) cm-1	Wedlock 1997
0.3	1053.4	Cl2 (aq, undissoc) + H2O (cr,l) → HOCl (aq, undissoc) + H+ (aq) + Cl- (aq)	Δ_rG°(298.15 K) = 19.74 ± 0.62 kJ/mol	Whitney 1941, note unc
0.3	115.11	H2O (g) → O (g) + 2 H (g)	Δ_rH°(0 K) = 917.80 ± 0.15 kJ/mol	Thorpe 2021
0.3	157.1	OH (g) → [OH]+ (g)	Δ_rH°(0 K) = 104989 ± 5 (×2.378) cm-1	Wiedmann 1992, note unc

Top 10 species with enthalpies of formation correlated to the Δ_fH° of HOCl (aq, undissoc)

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
66.2	Hypochlorite	[ClO]- (aq)		-110.488	± 0.076	kJ/mol	51.45265 ± 0.00095	14380-61-1*1000
66.2	Hypochlorous acid	HOCl (aq)		-110.488	± 0.076	kJ/mol	52.46004 ± 0.00095	7790-92-3*800
45.5	Hypochlorous acid	HOCl (g)	-73.844	-76.784	± 0.023	kJ/mol	52.46004 ± 0.00095	7790-92-3*0
43.3	Hydroxyl	OH (g)	37.274	37.514	± 0.022	kJ/mol	17.00734 ± 0.00031	3352-57-6*0
43.3	Hydroxyde	[OH]- (g)	-139.068	-139.034	± 0.022	kJ/mol	17.00789 ± 0.00031	14280-30-9*0
43.2	Water	H2O (l, eq.press.)		-285.806	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*589
43.2	Water	H2O (g, ortho)	-238.622	-241.810	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*1
43.2	Water	H2O (g, para)	-238.907	-241.810	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*2
43.2	Water	H2O (g)	-238.907	-241.810	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*0
43.2	Water	H2O (l)		-285.804	± 0.022	kJ/mol	18.01528 ± 0.00033	7732-18-5*590

Most Influential reactions involving HOCl (aq, undissoc)

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
0.996	1056.1	HOCl (aq, undissoc) → H+ (aq) + [ClO]- (aq)	Δ_rG°(298.15 K) = 43.019 ± 0.057 kJ/mol	Morris 1966
0.988	1052.1	HOCl (g) → HOCl (aq, undissoc)	Δ_rG°(298.15 K) = -16.067 ± 0.045 kJ/mol	Huthwelker 1995, Sander 2023, note unc
0.027	1053.4	Cl2 (aq, undissoc) + H2O (cr,l) → HOCl (aq, undissoc) + H+ (aq) + Cl- (aq)	Δ_rG°(298.15 K) = 19.74 ± 0.62 kJ/mol	Whitney 1941, note unc
0.013	1053.1	Cl2 (aq, undissoc) + H2O (cr,l) → HOCl (aq, undissoc) + H+ (aq) + Cl- (aq)	Δ_rG°(298.15 K) = 19.09 ± 0.50 (×1.756) kJ/mol	Yadav 1981, Deshwal 2015, est unc
0.010	1054.1	Cl2 (aq, undissoc) + [OH]- (aq) → HOCl (aq, undissoc) + Cl- (aq)	Δ_rG°(298.15 K) = -59.9 ± 1.0 kJ/mol	Yadav 1981, Hikita 1973
0.002	1056.2	HOCl (aq, undissoc) → H+ (aq) + [ClO]- (aq)	Δ_rH°(298.15 K) = 14.378 ± 1.10 kJ/mol	Morris 1966
0.000	1053.2	Cl2 (aq, undissoc) + H2O (cr,l) → HOCl (aq, undissoc) + H+ (aq) + Cl- (aq)	Δ_rG°(298.15 K) = 19.1 ± 4.0 kJ/mol	NBS Tables 1989
0.000	1054.2	Cl2 (aq, undissoc) + [OH]- (aq) → HOCl (aq, undissoc) + Cl- (aq)	Δ_rG°(298.15 K) = -14.53 ± 1. kcal/mol	Morris 1946, est unc
0.000	1052.5	HOCl (g) → HOCl (aq, undissoc)	Δ_rG°(298.15 K) = -16.0 ± 2 kJ/mol	Ourisson 1939, Sander 2023, est unc
0.000	1052.7	HOCl (g) → HOCl (aq, undissoc)	Δ_rG°(298.15 K) = -15.6 ± 2. kJ/mol	Hilal 2008, Sander 2023, est unc
0.000	1052.2	HOCl (g) → HOCl (aq, undissoc)	Δ_rH°(298.15 K) = -48.74 ± 2.4 kJ/mol	Huthwelker 1995, Sander 2023, note unc
0.000	1056.3	HOCl (aq, undissoc) → H+ (aq) + [ClO]- (aq)	Δ_rG°(298.15 K) = 43.1 ± 4.0 kJ/mol	NBS Tables 1989
0.000	1056.4	HOCl (aq, undissoc) → H+ (aq) + [ClO]- (aq)	Δ_rH°(298.15 K) = 13.8 ± 4.0 kJ/mol	NBS Tables 1989
0.000	1056.7	HOCl (aq, undissoc) → H+ (aq) + [ClO]- (aq)	Δ_rG°(298.15 K) = 42 ± 5 kJ/mol	Sand 1904, Ingham 1933, Williams 2022, est unc
0.000	1056.6	HOCl (aq, undissoc) → H+ (aq) + [ClO]- (aq)	Δ_rG°(298.15 K) = 42 ± 5 kJ/mol	Ingham 1933, Williams 2022, est unc
0.000	1052.3	HOCl (g) → HOCl (aq, undissoc)	Δ_rG°(298.15 K) = -13.8 ± 4.0 kJ/mol	NBS Tables 1989
0.000	1053.3	Cl2 (aq, undissoc) + H2O (cr,l) → HOCl (aq, undissoc) + H+ (aq) + Cl- (aq)	Δ_rH°(298.15 K) = 21.2 ± 4.0 (×2.89) kJ/mol	NBS Tables 1989
0.000	1052.4	HOCl (g) → HOCl (aq, undissoc)	Δ_rH°(298.15 K) = -42.2 ± 4.0 (×1.646) kJ/mol	NBS Tables 1989
0.000	1052.6	HOCl (g) → HOCl (aq, undissoc)	Δ_rH°(298.15 K) = -74. ± 30. kJ/mol	Ourisson 1939, Sander 2023, est unc

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. 1.172 of the Thermochemical Network (2024); available at ATcT.anl.gov
4		K. L. Caster, N. A. Seifert, B. Ruscic, A. W. Jasper, and K. Prozument, Dynamics of HCN, NHC, and HNCO Formation in the 193 nm Photodissociation of Formamide J. Phys. Chem. A (in press) (2024) [DOI: 10.1021/acs.jpca.4c02232]
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.