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].

Nitrous acid

Formula: HONO (g, cis)

CAS RN: 7782-77-6

ATcT ID: 7782-77-6*2

SMILES: N(=O)O

InChI: InChI=1S/HNO2/c2-1-3/h(H,2,3)

InChIKey: IOVCWXUNBOPUCH-UHFFFAOYSA-N

Hills Formula: H1N1O2

2D Image:

Aliases: HONO; Nitrous acid; Nytrosyl hydroxide; ONOH; HO-N=O; O=N-OH

Relative Molecular Mass: 47.01348 ± 0.00061

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
-71.37	-77.73	± 0.26	kJ/mol

3D Image of HONO (g, cis)

spin ON spin OFF

Top contributors to the provenance of Δ_fH° of HONO (g, cis)

The 13 contributors listed below account for 90.3% of the provenance of Δ_fH° of HONO (g, cis).

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
30.2	1993.1	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 141 ± 35 cm-1	Varma 1976
14.7	1993.2	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 100 ± 50 cm-1	Sironneau 2010, est unc
13.4	1994.12	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 0.30 ± 0.15 kcal/mol	Feller 2012, est unc
7.5	1994.11	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 0.43 ± 0.20 kcal/mol	Karton 2011
4.8	1993.3	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 0.506 ± 0.250 kcal/mol	Jones 1951
4.7	1993.5	HONO (g, trans) → HONO (g, cis)	Δ_rG°(277 K) = 0.649 ± 0.15 (×1.682) kcal/mol	Bongartz 1991, 3rd Law, note unc3
3.9	1982.11	HONO (g, cis) → H (g) + 2 O (g) + N (g)	Δ_rH°(0 K) = 299.31 ± 0.30 kcal/mol	Karton 2011
3.3	1994.10	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 0.43 ± 0.30 kcal/mol	Karton 2011
2.2	1982.12	HONO (g, cis) → H (g) + 2 O (g) + N (g)	Δ_rH°(0 K) = 299.24 ± 0.4 kcal/mol	Feller 2012
1.6	1999.8	NO (g) + ONO (g) + H2O (g) → 2 HONO (g)	Δ_rG°(298.15 K) = -1.44 ± 0.10 kJ/mol	Vosper 1976, 3rd Law
1.2	1483.1	NO (g) → N (g) + O (g)	Δ_rH°(0 K) = 52400 ± 10 cm-1	Callear 1970
1.2	1483.2	NO (g) → N (g) + O (g)	Δ_rH°(0 K) = 52400 ± 10 cm-1	Dingle 1975
1.1	1982.10	HONO (g, cis) → H (g) + 2 O (g) + N (g)	Δ_rH°(0 K) = 299.18 ± 0.56 kcal/mol	Karton 2011

Top 10 species with enthalpies of formation correlated to the Δ_fH° of HONO (g, cis)

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
31.5	Nitrous acid anion	[HONO]- (g, cis)	-105.84	-110.46	± 0.78	kJ/mol	47.01403 ± 0.00061	256393-36-9*2
31.5	Nitrous acid anion	[HONO]- (g)	-105.84	-109.31	± 0.78	kJ/mol	47.01403 ± 0.00061	256393-36-9*0
28.2	Nitrous acid	HONO (g, trans)	-72.986	-79.130	± 0.078	kJ/mol	47.01348 ± 0.00061	7782-77-6*1
28.2	Nitrous acid	HONO (g)	-72.986	-78.643	± 0.078	kJ/mol	47.01348 ± 0.00061	7782-77-6*0
23.3	Nitric oxide	NO (g)	90.627	91.131	± 0.064	kJ/mol	30.00614 ± 0.00031	10102-43-9*0
23.3	Nitrogen dioxide	ONO (g)	36.866	34.059	± 0.064	kJ/mol	46.00554 ± 0.00060	10102-44-0*0
23.3	Nitrosyl ion	[NO]+ (g)	984.494	984.489	± 0.064	kJ/mol	30.00559 ± 0.00031	14452-93-8*0
22.7	Dinitrogen tetraoxide	O2NNO2 (g)	20.17	10.88	± 0.14	kJ/mol	92.0111 ± 0.0012	10544-72-6*0
22.5	Nitrosyl chloride	ClNO (g)	54.461	52.559	± 0.067	kJ/mol	65.45884 ± 0.00095	2696-92-6*0
21.9	Dioxohydrazine	ONNO (g, cis)	172.91	171.14	± 0.14	kJ/mol	60.01228 ± 0.00062	16824-89-8*2

Most Influential reactions involving HONO (g, cis)

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
0.902	1986.1	[HONO]- (g, cis) → HONO (g, cis)	Δ_rH°(0 K) = 0.356 ± 0.008 eV	Oliveira 2016
0.333	1993.1	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 141 ± 35 cm-1	Varma 1976
0.249	1984.8	HONO (g, cis) → [HONO]+ (g, cis)	Δ_rH°(0 K) = 11.253 ± 0.040 eV	Ruscic W1RO
0.163	1993.2	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 100 ± 50 cm-1	Sironneau 2010, est unc
0.148	1994.12	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 0.30 ± 0.15 kcal/mol	Feller 2012, est unc
0.083	1994.11	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 0.43 ± 0.20 kcal/mol	Karton 2011
0.075	1984.4	HONO (g, cis) → [HONO]+ (g, cis)	Δ_rH°(0 K) = 11.223 ± 0.073 eV	Ruscic G4
0.053	1993.3	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 0.506 ± 0.250 kcal/mol	Jones 1951
0.052	1993.5	HONO (g, trans) → HONO (g, cis)	Δ_rG°(277 K) = 0.649 ± 0.15 (×1.682) kcal/mol	Bongartz 1991, 3rd Law, note unc3
0.046	1984.3	HONO (g, cis) → [HONO]+ (g, cis)	Δ_rH°(0 K) = 11.266 ± 0.093 eV	Ruscic G3X
0.046	1984.7	HONO (g, cis) → [HONO]+ (g, cis)	Δ_rH°(0 K) = 11.164 ± 0.075 (×1.242) eV	Ruscic CBS-n
0.040	1984.6	HONO (g, cis) → [HONO]+ (g, cis)	Δ_rH°(0 K) = 11.281 ± 0.099 eV	Ruscic CBS-n
0.040	1982.11	HONO (g, cis) → H (g) + 2 O (g) + N (g)	Δ_rH°(0 K) = 299.31 ± 0.30 kcal/mol	Karton 2011
0.037	1994.10	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 0.43 ± 0.30 kcal/mol	Karton 2011
0.023	1986.9	[HONO]- (g, cis) → HONO (g, cis)	Δ_rH°(0 K) = 0.347 ± 0.050 eV	Ruscic W1RO
0.022	1982.12	HONO (g, cis) → H (g) + 2 O (g) + N (g)	Δ_rH°(0 K) = 299.24 ± 0.4 kcal/mol	Feller 2012
0.015	1986.5	[HONO]- (g, cis) → HONO (g, cis)	Δ_rH°(0 K) = 0.398 ± 0.061 eV	Ruscic G4
0.011	1982.10	HONO (g, cis) → H (g) + 2 O (g) + N (g)	Δ_rH°(0 K) = 299.18 ± 0.56 kcal/mol	Karton 2011
0.009	1994.13	HONO (g, trans) → HONO (g, cis)	Δ_rH°(0 K) = 1.6 ± 2.5 kJ/mol	Klopper 2010a, est unc
0.008	1986.4	[HONO]- (g, cis) → HONO (g, cis)	Δ_rH°(0 K) = 0.382 ± 0.085 eV	Ruscic G3X

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.