Selected ATcT [1, 2] enthalpy of formation based on version 1.124 of the Thermochemical Network [3]

This version of ATcT results was generated by additional expansion of version 1.122x [4] to include additional information relevant to the study of thermophysical and thermochemical properties of CH2 and CH3 using nonrigid rotor anharmonic oscillator (NRRAO) partition functions [5], the development and benchmarking of a state-of-the-art computational approach that aims to reproduce total atomization energies of small molecules within 10–15 cm^-1 [6], as well as the study of the reversible reaction C₂H₃ + H₂ ⇌ C₂H₄ + H ⇌ C₂H₅ [7]

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
-38.563	-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 12 contributors listed below account for 90.1% 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
47.9	1602.1	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
24.4	1601.5	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	1601.4	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
3.4	1602.8	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	1602.3	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
1.0	1668.1	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
0.6	1601.3	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	1599.7	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	1600.7	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	1601.1	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	1662.3	(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	1668.3	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

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)	944.274	937.319	± 0.029	kJ/mol	17.03001 ± 0.00022	19496-55-0*0
51.3	Ammonia	NH3 (aq, undissoc)		-80.882	± 0.053	kJ/mol	17.03056 ± 0.00022	7664-41-7*1000
49.3	Ammonium	[NH4]+ (aq)		-133.074	± 0.056	kJ/mol	18.03795 ± 0.00029	14798-03-9*800
49.2	Ammonia	NH3 (aq)		-77.030	± 0.056	kJ/mol	17.03056 ± 0.00022	7664-41-7*800
47.6	Ammonium hydroxide	NH4OH (aq, undissoc)		-366.678	± 0.061	kJ/mol	35.04584 ± 0.00047	1336-21-6*1000
46.0	Ammonium hydroxide	NH4OH (aq)		-362.826	± 0.062	kJ/mol	35.04584 ± 0.00047	1336-21-6*800
43.9	Ammonium chloride	(NH4)Cl (cr)	-311.553	-314.714	± 0.062	kJ/mol	53.49120 ± 0.00095	12125-02-9*510
18.5	Azanylium	[NH2]+ (g)	1266.57	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
18.1	Ammonium bromide	(NH4)Br (cr)	-253.64	-270.22	± 0.15	kJ/mol	97.9425 ± 0.0010	12124-97-9*510

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	1719.1	(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	1592.1	NH3 (g) → [NH3]+ (g)	Δ_rH°(0 K) = 82158.751 ± 0.032 cm-1	Seiler 2003
0.775	1612.1	NH4 (g) → NH3 (g) + H (g)	Δ_rH°(0 K) = -0.130 ± 0.005 eV	Aue 1972
0.715	6107.1	C6H6 (g) + [NH2]- (g) → [C6H5]- (g) + NH3 (g)	Δ_rG°(300 K) = -3.557 ± 0.047 kcal/mol	Davico 1995
0.529	1663.1	NH3 (g) → NH3 (aq, undissoc)	Δ_rH°(298.15 K) = -8.448 ± 0.015 kcal/mol	Vanderzee 1972
0.516	2561.1	CH3NH2 (g) + [NH2]- (g) → [CH3NH]- (g) + NH3 (g)	Δ_rG°(296 K) = -0.51 ± 0.20 kcal/mol	MacKay 1976, note unc2
0.479	1602.1	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
0.449	2967.9	CO (g) + [NH4]+ (g) → [HCO]+ (g) + NH3 (g)	Δ_rH°(0 K) = 259.89 ± 0.3 kJ/mol	Czako 2008
0.437	2438.1	[CH2CH]- (g) + NH3 (g) → [NH2]- (g) + CH2CH2 (g)	Δ_rG°(298.15 K) = -4.54 ± 0.24 kcal/mol	Ervin 1990
0.434	1606.8	[NH4]+ (g) → NH3 (g) + H+ (g)	Δ_rH°(0 K) = 846.40 ± 0.3 kJ/mol	Czako 2008
0.371	1595.9	[NH3]- (g) → NH3 (g)	Δ_rH°(0 K) = -1.41 ± 0.04 eV	Puzzarini 2008
0.360	6498.2	[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
0.299	1627.1	NH3 (g) → [NH2]+ (g) + H (g)	Δ_rH°(0 K) = 15.765 ± 0.002 eV	Song 2001a, note unc2
0.298	2583.1	CH4 (g) + NH3 (g) → CH3N (g) + 2 H2 (g)	Δ_rH°(0 K) = 427.99 ± 2.0 kJ/mol	Klippenstein 2017
0.284	1875.1	NH3 (g) + H2O (g) → HNOH (g, trans) + 3/2 H2 (g)	Δ_rH°(0 K) = 378.46 ± 1.5 kJ/mol	Klippenstein 2017
0.263	1911.1	NH3 (g) + H2O (g) → NOH (g) + 2 H2 (g)	Δ_rH°(0 K) = 495.05 ± 1.5 kJ/mol	Klippenstein 2017
0.253	1841.1	NH2OH (g, trans) + H2O (g) → H2O2 (g) + NH3 (g)	Δ_rH°(0 K) = 24.9 ± 0.2 kcal/mol	Feller 2003, est unc
0.252	1947.1	NH3 (g) + 2 H2O (g) → HN(O)O (g) + 3 H2 (g)	Δ_rH°(0 K) = 480.58 ± 2.0 kJ/mol	Klippenstein 2017
0.252	1840.1	NH2OH (g, trans) + H2 (g) → H2O (g) + NH3 (g)	Δ_rH°(0 K) = -58.4 ± 0.2 kcal/mol	Feller 2003, est unc
0.244	1601.5	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. 1.124 of the Thermochemical Network, Argonne National Laboratory, Lemont, Illinois 2022; available at ATcT.anl.gov [DOI: 10.17038/CSE/1885923]
4		Y. Ren, L. Zhou, A. Mellouki, V. Daële, M. Idir, S. S. Brown, B. Ruscic, Robert S. Paton, M. R. McGillen, and A. R. Ravishankara, Reactions of NO3 with Aromatic Aldehydes: Gas-Phase Kinetics and Insights into the Mechanism of the Reaction. Atmos. Chem. Phys. 21, 13537-13551 (2021) [DOI: 10.5194/acp2021-228]
5		B. Ruscic and D. H. Bross, Active Thermochemical Tables: The Thermophysical and Thermochemical Properties of Methyl, CH3, and Methylene, CH2, Corrected for Nonrigid Rotor and Anharmonic Oscillator Effects. Mol. Phys. e1969046 (2021) [DOI: 10.1080/00268976.2021.1969046]
6		J. H. Thorpe, J. L. Kilburn, D. Feller, P. B. Changala, D. H. Bross, B. Ruscic, and J. F. Stanton, Elaborated Thermochemical Treatment of HF, CO, N2, and H2O: Insight into HEAT and Its Extensions J. Chem. Phys. 155, 184109 (2021) [DOI: 10.1063/5.0069322]
7		T. L. Nguyen, D. H. Bross, B. Ruscic, G. B. Ellison, and J. F. Stanton, Mechanism, Thermochemistry, and Kinetics of the Reversible Reactions: C2H3 + H2 ⇌ C2H4 + H ⇌ C2H5. Faraday Discuss. , (Advance Article) (2022) [DOI: 10.1039/D1FD00124H]
8		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]
9		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 [8,9]).
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.