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].

Ammonia

Formula: NH3 (g)

CAS RN: 7664-41-7

ATcT ID: 7664-41-7*0

SMILES: N

InChI: InChI=1S/H3N/h1H3

InChIKey: QGZKDVFQNNGYKY-UHFFFAOYSA-N

Hills Formula: H3N1

2D Image:

Aliases: NH3; Ammonia; Azane; Lambda1-azane; Nitrogen hydride; Nitrogen trihydride; Spirit of Hartshorn; Nitro-Sil; R717; UN1005; UN2073; UN2672

Relative Molecular Mass: 17.03056 ± 0.00022

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
-38.564	-45.556	± 0.029	kJ/mol

3D Image of NH3 (g)

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Top contributors to the provenance of Δ_fH° of NH3 (g)

The 14 contributors listed below account for 90.2% of the provenance of Δ_fH° of NH3 (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
47.6	1662.1	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rH°(298.15 K) = -10.885 ± 0.010 kcal/mol	Larson 1923, Vanderzee 1972
24.3	1661.5	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rH°(298.15 K) = -10.875 ± 0.014 kcal/mol	Schulz 1966, Vanderzee 1972
9.7	1661.4	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rH°(298.15 K) = -10.910 ± 0.015 (×1.477) kcal/mol	Larson 1924, Vanderzee 1972
3.3	1662.8	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rG°(635 K) = 20.084 ± 0.157 kJ/mol	Schulz 1966, 3rd Law
1.0	1731.1	N2 (g) + 3 H2O (cr,l) + 2 H+ (aq) → 3/2 O2 (g) + 2 [NH4]+ (aq)	Δ_rH°(298.15 K) = 141.292 ± 0.119 kcal/mol	Vanderzee 1972c
1.0	1662.3	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rG°(686 K) = 6.165 ± 0.068 kcal/mol	Larson 1923, 3rd Law, est unc
0.6	1661.3	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rH°(823 K) = -53.88 ± 0.19 (×1.957) kJ/mol	Wittig 1959
0.6	1659.7	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rH°(776.15 K) = -12.656 ± 0.089 kcal/mol	Haber 1915
0.3	1660.7	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rG°(1075 K) = 16.924 ± 0.11 kcal/mol	Haber 1915c, 3rd Law, est unc
0.3	1661.1	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rG°(1125 K) = 18.333 ± 0.11 kcal/mol	Haber 1915b, 3rd Law, est unc
0.3	1725.3	(NH4)NO3 (cr,l) → N2 (g) + 1/2 O2 (g) + 2 H2O (cr,l)	Δ_rH°(293.65 K) = -49.44 ± 0.06 kcal/mol	Becker 1934
0.2	1731.3	N2 (g) + 3 H2O (cr,l) + 2 H+ (aq) → 3/2 O2 (g) + 2 [NH4]+ (aq)	Δ_rH°(298.15 K) = 141.226 ± 0.239 kcal/mol	Becker 1934, as quoted by CODATA Key Vals
0.2	1650.4	NH3 (g) → N (g) + 3 H (g)	Δ_rH°(0 K) = 1157.46 ± 0.56 kJ/mol	Harding 2008
0.2	1662.5	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rG°(700 K) = 6.530 ± 0.14 kcal/mol	Larson 1923, 3rd Law, est unc

Top 10 species with enthalpies of formation correlated to the Δ_fH° of NH3 (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
99.9	Azanylium	[NH3]+ (g)	944.273	937.319	± 0.029	kJ/mol	17.03001 ± 0.00022	19496-55-0*0
51.1	Ammonia	NH3 (aq, undissoc)		-80.884	± 0.053	kJ/mol	17.03056 ± 0.00022	7664-41-7*1000
49.2	Ammonium	[NH4]+ (aq)		-133.076	± 0.056	kJ/mol	18.03795 ± 0.00029	14798-03-9*800
49.1	Ammonia	NH3 (aq)		-77.033	± 0.056	kJ/mol	17.03056 ± 0.00022	7664-41-7*800
47.9	Ammonium hydroxide	NH4OH (aq, undissoc)		-366.688	± 0.059	kJ/mol	35.04584 ± 0.00047	1336-21-6*1000
46.2	Ammonium hydroxide	NH4OH (aq)		-362.837	± 0.061	kJ/mol	35.04584 ± 0.00047	1336-21-6*800
43.8	Ammonium chloride	(NH4)Cl (cr)	-311.555	-314.717	± 0.062	kJ/mol	53.49120 ± 0.00095	12125-02-9*510
19.7	Ammonium bromide	(NH4)Br (cr)	-253.27	-269.84	± 0.14	kJ/mol	97.9425 ± 0.0010	12124-97-9*510
18.5	Azanylium	[NH2]+ (g)	1266.56	1264.49	± 0.11	kJ/mol	16.02207 ± 0.00016	15194-15-7*0
18.5	Amidogen	NH2 (g)	188.92	186.03	± 0.11	kJ/mol	16.02262 ± 0.00016	13770-40-6*0

Most Influential reactions involving NH3 (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
1.000	1782.1	(NH4)2O (cr,l) → NH4OH (cr,l) + NH3 (g)	Δ_rH°(187.4 K) = 7.523 ± 0.050 kcal/mol	Hildenbrand 1953, est unc
0.999	1652.1	NH3 (g) → [NH3]+ (g)	Δ_rH°(0 K) = 82158.751 ± 0.032 cm-1	Seiler 2003
0.930	1721.1	3 NF2NF2 (g) + 16 NH3 (g) → 12 (NH4)F (cr,l) + 5 N2 (g)	Δ_rH°(298.15 K) = -4809.0 ± 2.7 kJ/mol	Armstrong 1959a
0.775	1672.1	NH4 (g) → NH3 (g) + H (g)	Δ_rH°(0 K) = -0.130 ± 0.005 eV	Aue 1972
0.712	6861.1	C6H6 (g) + [NH2]- (g) → [C6H5]- (g) + NH3 (g)	Δ_rG°(300 K) = -3.557 ± 0.047 kcal/mol	Davico 1995
0.529	1726.1	NH3 (g) → NH3 (aq, undissoc)	Δ_rH°(298.15 K) = -8.448 ± 0.015 kcal/mol	Vanderzee 1972
0.516	2694.1	CH3NH2 (g) + [NH2]- (g) → [CH3NH]- (g) + NH3 (g)	Δ_rG°(296 K) = -0.51 ± 0.20 kcal/mol	MacKay 1976, note unc2
0.476	1662.1	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rH°(298.15 K) = -10.885 ± 0.010 kcal/mol	Larson 1923, Vanderzee 1972
0.442	3100.9	CO (g) + [NH4]+ (g) → [HCO]+ (g) + NH3 (g)	Δ_rH°(0 K) = 259.89 ± 0.3 kJ/mol	Czako 2008
0.437	2571.1	[CH2CH]- (g) + NH3 (g) → [NH2]- (g) + CH2CH2 (g)	Δ_rG°(298.15 K) = -4.54 ± 0.24 kcal/mol	Ervin 1990
0.425	1666.8	[NH4]+ (g) → NH3 (g) + H+ (g)	Δ_rH°(0 K) = 846.40 ± 0.3 kJ/mol	Czako 2008
0.371	1655.9	[NH3]- (g) → NH3 (g)	Δ_rH°(0 K) = -1.41 ± 0.04 eV	Puzzarini 2008
0.360	7386.2	[NH(CHCHCHCHCH)]+ (g) + NH3 (g) → N(CHCHCHCHCH) (g) + [NH4]+ (g)	Δ_rG°(350 K) = 80.5 ± 2.0 kJ/mol	Hunter 1998, Taft 1986, est unc
0.316	2673.11	[CH3NH3]+ (g) + NH3 (g) → CH3NH2 (g) + [NH4]+ (g)	Δ_rH°(0 K) = 11.30 ± 0.40 kcal/mol	Lee 2021, est unc
0.307	1936.1	NH3 (g) + H2O (g) → HNOH (g, trans) + 3/2 H2 (g)	Δ_rH°(0 K) = 378.46 ± 1.5 kJ/mol	Klippenstein 2017
0.302	1687.1	NH3 (g) → [NH2]+ (g) + H (g)	Δ_rH°(0 K) = 15.765 ± 0.002 eV	Song 2001a, note unc2
0.246	2716.1	CH4 (g) + NH3 (g) → CH3N (g) + 2 H2 (g)	Δ_rH°(0 K) = 427.99 ± 2.0 kJ/mol	Klippenstein 2017
0.244	1903.1	NH2OH (g, trans) + H2O (g) → HOOH (g) + NH3 (g)	Δ_rH°(0 K) = 24.9 ± 0.2 kcal/mol	Feller 2003, est unc
0.243	1900.2	NH3 (g) + H2O (g) → NH2OH (g, trans) + H2 (g)	Δ_rH°(0 K) = 58.4 ± 0.2 kcal/mol	Feller 2003, est unc
0.243	1661.5	1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)	Δ_rH°(298.15 K) = -10.875 ± 0.014 kcal/mol	Schulz 1966, Vanderzee 1972

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.