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].

Water

Formula: H2O (l, eq.press.)
CAS RN: 7732-18-5
ATcT ID: 7732-18-5*589
SMILES: O
InChI: InChI=1S/H2O/h1H2
InChIKey: XLYOFNOQVPJJNP-UHFFFAOYSA-N
Hills Formula: H2O1

2D Image:

O
Aliases: Water; Oxidane; HOH; Dihydrogen oxide; Dihydrogen monoxide; Hydrogen oxide; Oxygen dyhydride; H2O
Relative Molecular Mass: 18.01528 ± 0.00033

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
-285.806± 0.022kJ/mol

Top contributors to the provenance of ΔfH° of H2O (l, eq.press.)

The 20 contributors listed below account only for 65.0% of the provenance of ΔfH° of H2O (l, eq.press.).
A total of 305 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
29.6125.2 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
8.82373.7 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.578 ± 0.078 kJ/molSchley 2010
8.02375.1 2 H2 (g) + C (graphite) → CH4 (g) ΔrG°(1165 K) = 37.521 ± 0.068 kJ/molSmith 1946, note COf, 3rd Law
2.0115.11 H2O (g) → O (g) + 2 H (g) ΔrH°(0 K) = 917.80 ± 0.15 kJ/molThorpe 2021
1.8157.1 OH (g) → [OH]+ (g) ΔrH°(0 K) = 104989 ± 5 (×2.378) cm-1Wiedmann 1992, note unc
1.5167.6 H2O (g) → [OH]+ (g) + H (g) ΔrH°(0 K) = 18.1183 ± 0.0015 (×1.067) eVBodi 2014
1.4152.1 OH (g) → O (g) + H (g) ΔrH°(0 K) = 35580 ± 15 cm-1Sun 2020
1.31731.1 N2 (g) + 3 H2O (cr,l) + 2 H+ (aq) → 3/2 O2 (g) + 2 [NH4]+ (aq) ΔrH°(298.15 K) = 141.292 ± 0.119 kcal/molVanderzee 1972c
1.2169.1 [OH]- (g) → O- (g) + H (g) ΔrH°(0 K) = 4.7796 ± 0.0010 (×2) eVMartin 2001, est unc
1.22373.4 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.61 ± 0.21 kJ/molDale 2002
1.12268.11 CO (g) → C (g) + O (g) ΔrH°(0 K) = 1071.92 ± 0.10 kJ/molThorpe 2021
1.0167.7 H2O (g) → [OH]+ (g) + H (g) ΔrH°(0 K) = 18.1190 ± 0.002 eVBodi 2014
0.8167.5 H2O (g) → [OH]+ (g) + H (g) ΔrH°(0 K) = 18.1177 ± 0.0015 (×1.477) eVBodi 2014
0.72373.8 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.482 ± 0.260 kJ/molHaloua 2015
0.72373.6 CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (cr,l) ΔrH°(298.15 K) = -890.44 ± 0.26 kJ/molGOMB Ref Calorimeter, Alexandrov 2002
0.7175.1 [OH]+ (g) → O+ (g) + H (g) ΔrH°(0 K) = 40412.0 ± 2.2 cm-1Moselhy 1975, note unc
0.72285.3 CO (g) + H2O (g) → CO2 (g) + H2 (g) ΔrG°(893 K) = -6.369 ± 0.283 kJ/molMeyer 1938, note COi, 3rd Law
0.51542.4 NNO (g) + CO (g) → CO2 (g) + N2 (g) ΔrH°(293.15 K) = -365.642 ± 0.243 kJ/molFenning 1933, note N2Oa
0.52278.2 CO (g) → C+ (g) + O (g) ΔrH°(0 K) = 22.3713 ± 0.0015 eVNg 2007
0.5225.4 HOOH (g) → 2 H (g) + 2 O (g) ΔrH°(0 K) = 1054.84 ± 0.56 kJ/molHarding 2008

Top 10 species with enthalpies of formation correlated to the ΔfH° of H2O (l, eq.press.)

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 WaterH2O (l)O-285.804± 0.022kJ/mol18.01528 ±
0.00033		7732-18-5*590
100.0 WaterH2O (g, ortho)O-238.622-241.810± 0.022kJ/mol18.01528 ±
0.00033		7732-18-5*1
100.0 WaterH2O (g, para)O-238.907-241.810± 0.022kJ/mol18.01528 ±
0.00033		7732-18-5*2
100.0 WaterH2O (g)O-238.907-241.810± 0.022kJ/mol18.01528 ±
0.00033		7732-18-5*0
100.0 Oxonium[H3O]+ (aq)[OH3+]-285.804± 0.022kJ/mol19.02267 ±
0.00037		13968-08-6*800
100.0 WaterH2O (cr,l)O-286.276-285.804± 0.022kJ/mol18.01528 ±
0.00033		7732-18-5*500
100.0 WaterH2O (cr, l, eq.press.)O-286.278-285.806± 0.022kJ/mol18.01528 ±
0.00033		7732-18-5*499
99.9 WaterH2O (cr)O-286.276-292.717± 0.022kJ/mol18.01528 ±
0.00033		7732-18-5*510
99.9 WaterH2O (cr, eq.press.)O-286.278-292.719± 0.022kJ/mol18.01528 ±
0.00033		7732-18-5*509
99.8 HydroxylOH (g)[OH]37.27437.514± 0.022kJ/mol17.00734 ±
0.00031		3352-57-6*0

Most Influential reactions involving H2O (l, eq.press.)

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
1.000130.1 H2O (l, eq.press.) → H2O (cr, l, eq.press.) ΔrH°(298.15 K) = 0.0 ± 0.0 cm-1triv
0.338132.5 H2O (l, eq.press.) → H2O (g) ΔrG°(298.15 K) = 8.560013 ± 0.000348 kJ/molWagner 2002
0.311135.4 H2O (l, eq.press.) → H2O (g) ΔrG°(300 K) = 8.340252 ± 0.000363 kJ/molWagner 2002
0.250128.4 H2O (l, eq.press.) → H2O (l) ΔrG°(298.15 K) = 0.001750 ± 0.00001 kJ/molWagner 2002, est unc
0.250128.1 H2O (l, eq.press.) → H2O (l) ΔrH°(273.16 K) = 0.001824 ± 0.00001 kJ/molWagner 2002, est unc
0.250128.2 H2O (l, eq.press.) → H2O (l) ΔrG°(273.16 K) = 0.001791 ± 0.00001 kJ/molWagner 2002, est unc
0.250128.3 H2O (l, eq.press.) → H2O (l) ΔrH°(298.15 K) = 0.001615 ± 0.00001 kJ/molWagner 2002, est unc
0.117135.3 H2O (l, eq.press.) → H2O (g) ΔrG°(290 K) = 9.533891 ± 0.000296 (×2) kJ/molWagner 2002
0.092135.5 H2O (l, eq.press.) → H2O (g) ΔrG°(310 K) = 7.160506 ± 0.000470 (×1.414) kJ/molWagner 2002
0.039208.1 2 H2O (l, eq.press.) → (H2O)2 (g) ΔrG°(270 K) = 29.1743 ± 0.0145 kJ/molWagner 2002
0.038207.1 2 H2O (l, eq.press.) → (H2O)2 (g) ΔrG°(273.16 K) = 28.6437 ± 0.0147 kJ/molWagner 2002
0.036208.2 2 H2O (l, eq.press.) → (H2O)2 (g) ΔrG°(280 K) = 27.5049 ± 0.0150 kJ/molWagner 2002
0.034208.3 2 H2O (l, eq.press.) → (H2O)2 (g) ΔrG°(290 K) = 25.8628 ± 0.0155 kJ/molWagner 2002
0.032207.2 2 H2O (l, eq.press.) → (H2O)2 (g) ΔrG°(298.15 K) = 24.5434 ± 0.0160 kJ/molWagner 2002
0.031208.4 2 H2O (l, eq.press.) → (H2O)2 (g) ΔrG°(300 K) = 24.2462 ± 0.0161 kJ/molWagner 2002
0.030208.5 2 H2O (l, eq.press.) → (H2O)2 (g) ΔrG°(310 K) = 22.6542 ± 0.0166 kJ/molWagner 2002
0.027208.6 2 H2O (l, eq.press.) → (H2O)2 (g) ΔrG°(320 K) = 21.0858 ± 0.0172 kJ/molWagner 2002
0.027135.2 H2O (l, eq.press.) → H2O (g) ΔrG°(280 K) = 10.741966 ± 0.000257 (×4.757) kJ/molWagner 2002
0.026208.7 2 H2O (l, eq.press.) → (H2O)2 (g) ΔrG°(330 K) = 19.5406 ± 0.0178 kJ/molWagner 2002
0.024135.6 H2O (l, eq.press.) → H2O (g) ΔrG°(320 K) = 5.994171 ± 0.000628 (×2.044) kJ/molWagner 2002
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.