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].

Hydroxylamine

Formula: NH2OH (aq, undissoc)

CAS RN: 7803-49-8

ATcT ID: 7803-49-8*1000

SMILES: NO

InChI: InChI=1S/H3NO/c1-2/h2H,1H2

InChIKey: AVXURJPOCDRRFD-UHFFFAOYSA-N

Hills Formula: H3N1O1

2D Image:

Aliases: NH2OH; Hydroxylamine; Hydroxyl amine; Hydroxyamine; Oxammonium; Oxyammonia; HDA; Telclean 1200A

Relative Molecular Mass: 33.02996 ± 0.00037

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
	-97.1	± 2.2	kJ/mol

Top contributors to the provenance of Δ_fH° of NH2OH (aq, undissoc)

The 3 contributors listed below account for 99.8% of the provenance of Δ_fH° of NH2OH (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
42.3	1911.1	3 NH2OH (aq, undissoc) → N2 (g) + NH3 (aq, undissoc) + 3 H2O (cr,l)	Δ_rH°(298.15 K) = -153.7 ± 2.4 kcal/mol	Thomsen 1882, Ellingson 1915, Berthelot 1877, Lumme 1965, Muhammad 1957, Svyentoslavskii 1909, Berthelot 1890, as quoted by NBS Tables
42.3	1911.2	3 NH2OH (aq, undissoc) → N2 (g) + NH3 (aq, undissoc) + 3 H2O (cr,l)	Δ_rH°(298.15 K) = -154.2 ± 2.4 kcal/mol	Thomsen 1882, Ellingson 1915, Berthelot 1877, Lumme 1965, Muhammad 1957, Svyentoslavskii 1909, Berthelot 1890, as quoted by NBS Tables
15.0	1910.1	NH2OH (cr,l) → NH2OH (aq, undissoc)	Δ_rH°(298.15 K) = 3.8 ± 1.0 (×1.325) kcal/mol	Berthelot 1892a, as quoted by NBS Tables

Top 10 species with enthalpies of formation correlated to the Δ_fH° of NH2OH (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
4.2	Hydroxylamine	NH2OH (cr,l)		-107.44	± 0.60	kJ/mol	33.02996 ± 0.00037	7803-49-8*500
2.9	Hydroxylamine	NH2OH (g)	-33.06	-43.43	± 0.42	kJ/mol	33.02996 ± 0.00037	7803-49-8*0
2.9	Hydroxylamine	NH2OH (g, trans)	-33.06	-43.44	± 0.42	kJ/mol	33.02996 ± 0.00037	7803-49-8*1
1.1	Ammonium hydroxide	NH4OH (aq, undissoc)		-366.688	± 0.059	kJ/mol	35.04584 ± 0.00047	1336-21-6*1000
1.0	Ammonium hydroxide	NH4OH (aq)		-362.837	± 0.061	kJ/mol	35.04584 ± 0.00047	1336-21-6*800

Most Influential reactions involving NH2OH (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
0.423	1911.1	3 NH2OH (aq, undissoc) → N2 (g) + NH3 (aq, undissoc) + 3 H2O (cr,l)	Δ_rH°(298.15 K) = -153.7 ± 2.4 kcal/mol	Thomsen 1882, Ellingson 1915, Berthelot 1877, Lumme 1965, Muhammad 1957, Svyentoslavskii 1909, Berthelot 1890, as quoted by NBS Tables
0.423	1911.2	3 NH2OH (aq, undissoc) → N2 (g) + NH3 (aq, undissoc) + 3 H2O (cr,l)	Δ_rH°(298.15 K) = -154.2 ± 2.4 kcal/mol	Thomsen 1882, Ellingson 1915, Berthelot 1877, Lumme 1965, Muhammad 1957, Svyentoslavskii 1909, Berthelot 1890, as quoted by NBS Tables
0.162	1910.1	NH2OH (cr,l) → NH2OH (aq, undissoc)	Δ_rH°(298.15 K) = 3.8 ± 1.0 (×1.325) kcal/mol	Berthelot 1892a, as quoted by NBS Tables

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. 1.176 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.