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].

Ammonium

Formula: [NH4]+ (aq)

CAS RN: 14798-03-9

ATcT ID: 14798-03-9*800

SMILES: [NH4+]

InChI: InChI=1S/H3N/h1H3/p+1

InChIKey: QGZKDVFQNNGYKY-UHFFFAOYSA-O

InChI: InChI=1S/H4N/h1H4/q+1

InChIKey: ROECXRZWTWXXKP-UHFFFAOYSA-N

Hills Formula: H4N1+

2D Image:

Aliases: [NH4]+; Ammonium; Ammonium ion; Ammonium cation; Ammonium ion (1+); Protonated ammonia; Monoprotonated ammonia

Relative Molecular Mass: 18.03795 ± 0.00029

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
	-133.076	± 0.056	kJ/mol

Top contributors to the provenance of Δ_fH° of [NH4]+ (aq)

The 17 contributors listed below account for 90.6% of the provenance of Δ_fH° of [NH4]+ (aq).

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
33.6	1726.1	NH3 (g) → NH3 (aq, undissoc)	Δ_rH°(298.15 K) = -8.448 ± 0.015 kcal/mol	Vanderzee 1972
11.5	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
8.4	1726.2	NH3 (g) → NH3 (aq, undissoc)	Δ_rH°(298.15 K) = -8.456 ± 0.030 kcal/mol	Stavaley 1971, Vanderzee 1972, as quoted by CODATA Key Vals
8.4	1726.7	NH3 (g) → NH3 (aq, undissoc)	Δ_rH°(298.15 K) = -8.456 ± 0.030 kcal/mol	Staveley 1971, Vanderzee 1972
5.8	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
4.4	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
4.4	1728.1	[NH4]+ (aq) → NH3 (aq, undissoc) + H+ (aq)	Δ_rG°(298.15 K) = 52.771 ± 0.020 kJ/mol	Bates 1950, Bates 1950, Bates 1949, Bates 1943, Bates 1946
3.0	1726.3	NH3 (g) → NH3 (aq, undissoc)	Δ_rH°(298.15 K) = -8.442 ± 0.050 kcal/mol	Thomsen 1873, Vanderzee 1972
2.3	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
1.9	1730.1	NH3 (g) + HON(O)O (aq) → [NH4]+ (aq) + [ON(O)O]- (aq)	Δ_rH°(298.15 K) = -87.23 ± 0.25 (×1.164) kJ/mol	Becker 1934, Vanderzee 1972a, as quoted by CODATA Key Vals
1.2	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
1.1	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
0.9	1729.3	NH3 (aq, undissoc) + H2O (cr,l) → [NH4]+ (aq) + [OH]- (aq)	Δ_rH°(298.15 K) = 0.920 ± 0.010 kcal/mol	Vanderzee 1972a
0.8	1722.6	(NH4)Cl (cr) → NH3 (g) + HCl (g)	Δ_rH°(298.15 K) = 42.20 ± 0.06 (×1.719) kcal/mol	Braune 1928, JANAF 3, 3rd Law
0.8	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
0.7	1726.4	NH3 (g) → NH3 (aq, undissoc)	Δ_rH°(298.15 K) = -8.475 ± 0.100 kcal/mol	Baud 1909, Vanderzee 1972
0.7	1728.5	[NH4]+ (aq) → NH3 (aq, undissoc) + H+ (aq)	Δ_rG°(298.15 K) = 52.732 ± 0.050 kJ/mol	Everett 1954, Olofsson 1975a, as quoted by CODATA Key Vals

Top 10 species with enthalpies of formation correlated to the Δ_fH° of [NH4]+ (aq)

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
99.7	Ammonia	NH3 (aq)		-77.033	± 0.056	kJ/mol	17.03056 ± 0.00022	7664-41-7*800
95.3	Ammonia	NH3 (aq, undissoc)		-80.884	± 0.053	kJ/mol	17.03056 ± 0.00022	7664-41-7*1000
93.0	Ammonium hydroxide	NH4OH (aq)		-362.837	± 0.061	kJ/mol	35.04584 ± 0.00047	1336-21-6*800
88.7	Ammonium hydroxide	NH4OH (aq, undissoc)		-366.688	± 0.059	kJ/mol	35.04584 ± 0.00047	1336-21-6*1000
87.8	Ammonium chloride	(NH4)Cl (cr)	-311.555	-314.717	± 0.062	kJ/mol	53.49120 ± 0.00095	12125-02-9*510
49.2	Azanylium	[NH3]+ (g)	944.273	937.319	± 0.029	kJ/mol	17.03001 ± 0.00022	19496-55-0*0
49.2	Ammonia	NH3 (g)	-38.564	-45.556	± 0.029	kJ/mol	17.03056 ± 0.00022	7664-41-7*0
39.4	Ammonium bromide	(NH4)Br (cr)	-253.27	-269.84	± 0.14	kJ/mol	97.9425 ± 0.0010	12124-97-9*510
17.5	Ammonium nitrate	(NH4)NO3 (cr,l)	-350.21	-365.17	± 0.18	kJ/mol	80.04344 ± 0.00095	6484-52-2*500
13.8	Ammonium hydroxide	NH4OH (aq, 1000 H2O)		-366.38	± 0.41	kJ/mol	35.04584 ± 0.00047	1336-21-6*839

Most Influential reactions involving [NH4]+ (aq)

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	1738.1	NH4OH (aq) → [NH4]+ (aq) + [OH]- (aq)	Δ_rH°(298.15 K) = 0 ± 0 cm-1	triv
0.951	1732.5	(NH4)Cl (cr) → [NH4]+ (aq) + Cl- (aq)	Δ_rG°(298.15 K) = -7.092 ± 0.020 kJ/mol	CODATA Key Vals
0.897	1734.2	(NH4)NO3 (cr,l) → [NH4]+ (aq) + [ON(O)O]- (aq)	Δ_rH°(298.15 K) = 25.544 ± 0.030 kJ/mol	Vanderzee 1980, Vanderzee 1980a, as quoted by CODATA Key Vals
0.786	1733.5	(NH4)Br (cr) → [NH4]+ (aq) + Br- (aq)	Δ_rG°(298.15 K) = -7.849 ± 0.040 kJ/mol	CODATA Key Vals
0.687	1728.1	[NH4]+ (aq) → NH3 (aq, undissoc) + H+ (aq)	Δ_rG°(298.15 K) = 52.771 ± 0.020 kJ/mol	Bates 1950, Bates 1950, Bates 1949, Bates 1943, Bates 1946
0.199	1733.3	(NH4)Br (cr) → [NH4]+ (aq) + Br- (aq)	Δ_rG°(298.15 K) = -1.883 ± 0.019 kcal/mol	Shults 1966, Stephenson 1968, est unc
0.162	1729.3	NH3 (aq, undissoc) + H2O (cr,l) → [NH4]+ (aq) + [OH]- (aq)	Δ_rH°(298.15 K) = 0.920 ± 0.010 kcal/mol	Vanderzee 1972a
0.109	1728.5	[NH4]+ (aq) → NH3 (aq, undissoc) + H+ (aq)	Δ_rG°(298.15 K) = 52.732 ± 0.050 kJ/mol	Everett 1954, Olofsson 1975a, as quoted by CODATA Key Vals
0.062	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
0.053	1734.3	(NH4)NO3 (cr,l) → [NH4]+ (aq) + [ON(O)O]- (aq)	Δ_rH°(298.15 K) = 25.418 ± 0.030 (×4.088) kJ/mol	Medvedev 1978, as quoted by CODATA Key Vals
0.026	1730.1	NH3 (g) + HON(O)O (aq) → [NH4]+ (aq) + [ON(O)O]- (aq)	Δ_rH°(298.15 K) = -87.23 ± 0.25 (×1.164) kJ/mol	Becker 1934, Vanderzee 1972a, as quoted by CODATA Key Vals
0.022	1732.4	(NH4)Cl (cr) → [NH4]+ (aq) + Cl- (aq)	Δ_rH°(298.15 K) = 3.533 ± 0.015 (×2.089) kcal/mol	Parker 1965, as quoted by CODATA Key Vals
0.020	1734.1	(NH4)NO3 (cr,l) → [NH4]+ (aq) + [ON(O)O]- (aq)	Δ_rH°(298.15 K) = 25.49 ± 0.20 kJ/mol	Becker 1934, Parker 1965, as quoted by CODATA Key Vals
0.019	1728.2	[NH4]+ (aq) → NH3 (aq, undissoc) + H+ (aq)	Δ_rH°(298.15 K) = 52.201 ± 0.118 kJ/mol	Bates 1950, Bates 1950, Bates 1949, Bates 1943, Bates 1946
0.015	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
0.013	1732.1	(NH4)Cl (cr) → [NH4]+ (aq) + Cl- (aq)	Δ_rH°(298.15 K) = 3.542 ± 0.005 (×8.175) kcal/mol	Vanderzee 1972a
0.008	1734.6	(NH4)NO3 (cr,l) → [NH4]+ (aq) + [ON(O)O]- (aq)	Δ_rG°(298.15 K) = -6.068 ± 0.080 (×3.914) kJ/mol	CODATA Key Vals
0.006	1731.2	N2 (g) + 3 H2O (cr,l) + 2 H+ (aq) → 3/2 O2 (g) + 2 [NH4]+ (aq)	Δ_rH°(298.15 K) = 141.110 ± 0.369 kcal/mol	Vanderzee 1972c
0.005	1729.2	NH3 (aq, undissoc) + H2O (cr,l) → [NH4]+ (aq) + [OH]- (aq)	Δ_rH°(298.15 K) = 0.865 ± 0.030 (×1.874) kcal/mol	Pitzer 1937
0.005	1734.4	(NH4)NO3 (cr,l) → [NH4]+ (aq) + [ON(O)O]- (aq)	Δ_rH°(298.15 K) = 25.86 ± 0.40 kJ/mol	Krestov 1972, as quoted by CODATA Key Vals

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.