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].

Hydrogen isocyanide

Formula: HNC (g)

CAS RN: 6914-07-4

ATcT ID: 6914-07-4*0

SMILES: [C]=N

SMILES: [C]=[NH]

InChI: InChI=1S/CHN/c1-2/h2H

InChIKey: QIUBLANJVAOHHY-UHFFFAOYSA-N

Hills Formula: C1H1N1

2D Image:

Aliases: HNC; Hydrogen isocyanide; Iminomethylidene; Isohydrocyanic acid; Hydroisocyanic acid; Nitriliomethanide; CNH; 18660-97-4

Relative Molecular Mass: 27.02538 ± 0.00081

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
192.06	192.44	± 0.32	kJ/mol

3D Image of HNC (g)

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

The 20 contributors listed below account only for 81.8% of the provenance of Δ_fH° of HNC (g).
A total of 53 contributors would be needed to account for 90% of the provenance.

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
23.8	2782.10	HCN (g) → HNC (g)	Δ_rH°(0 K) = 5236 ± 50 cm-1	Nguyen 2015c
7.8	2783.3	HCN (g) → HNC (g)	Δ_rH°(0 K) = 14.88 ± 0.25 kcal/mol	Karton 2011
6.1	2782.13	HCN (g) → HNC (g)	Δ_rH°(0 K) = 5312.8 ± 60 (×1.646) cm-1	Makhnev 2018
6.0	2776.11	HNC (g) → C (g) + N (g) + H (g)	Δ_rH°(0 K) = 288.27 ± 0.30 kcal/mol	Karton 2011
5.9	2782.11	HCN (g) → HNC (g)	Δ_rH°(0 K) = 5185.64 ± 100 cm-1	van Mourik 2001, Barber 2002, est unc, Sun 2015
5.9	2782.12	HCN (g) → HNC (g)	Δ_rH°(0 K) = 5201 ± 100 cm-1	Dawes 2009, est unc
5.4	2783.14	HCN (g) → HNC (g)	Δ_rH°(0 K) = 14.93 ± 0.30 kcal/mol	Burke 2021
3.7	2783.13	HCN (g) → HNC (g)	Δ_rH°(0 K) = 62.55 ± 1.5 kJ/mol	Klippenstein 2017
3.0	2783.2	HCN (g) → HNC (g)	Δ_rH°(0 K) = 14.94 ± 0.4 kcal/mol	Karton 2011
2.1	2823.8	CH3NC (g) + HCN (g) → CH3CN (g) + HNC (g)	Δ_rH°(0 K) = -40.97 ± 1.5 kJ/mol	Klippenstein 2017
1.9	2783.4	HCN (g) → HNC (g)	Δ_rH°(0 K) = 14.69 ± 0.50 kcal/mol	Puzzarini 2010, est unc
1.7	2776.10	HNC (g) → C (g) + N (g) + H (g)	Δ_rH°(0 K) = 288.14 ± 0.56 kcal/mol	Karton 2011
1.3	2783.8	HCN (g) → HNC (g)	Δ_rH°(0 K) = 62.7 ± 2.5 kJ/mol	Vogiatzis 2014, est unc
1.3	2783.7	HCN (g) → HNC (g)	Δ_rH°(0 K) = 62.7 ± 2.5 kJ/mol	Klopper 2010a, est unc
1.1	2823.7	CH3NC (g) + HCN (g) → CH3CN (g) + HNC (g)	Δ_rH°(0 K) = -40.9 ± 2.0 kJ/mol	Vogiatzis 2014, est unc
1.1	2823.6	CH3NC (g) + HCN (g) → CH3CN (g) + HNC (g)	Δ_rH°(0 K) = -40.6 ± 2.0 kJ/mol	Klopper 2010a, est unc
1.0	2822.12	CH3CN (g) → CH3NC (g)	Δ_rH°(0 K) = 103.26 ± 0.7 kJ/mol	Nguyen 2018
0.9	2781.4	HCN (g) → HNC (g)	Δ_rH°(0 K) = 5162 ± 250 cm-1	Baraban 2015, note unc
0.4	2783.1	HCN (g) → HNC (g)	Δ_rH°(0 K) = 14.85 ± 1.1 kcal/mol	Karton 2011
0.3	2823.5	CH3NC (g) + HCN (g) → CH3CN (g) + HNC (g)	Δ_rH°(0 K) = -9.93 ± 0.85 kcal/mol	Ruscic W1RO

Top 10 species with enthalpies of formation correlated to the Δ_fH° of HNC (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
99.7	Hydrogen isocyanide anion	[HNC]- (g)	191.61	191.80	± 0.32	kJ/mol	27.02593 ± 0.00081	96913-22-3*0
31.8	Hydrogen isocyanide cation	[HNC]+ (g)	1351.52	1351.48	± 0.83	kJ/mol	27.02483 ± 0.00081	74158-11-5*0
25.1	Hydrogen cyanide	HCN (g)	129.677	129.293	± 0.087	kJ/mol	27.02538 ± 0.00081	74-90-8*0
25.1	Hydrogen cyanide anion	[HCN]- (g)	129.526	129.047	± 0.087	kJ/mol	27.02593 ± 0.00081	12334-27-9*0
23.9	Cyanide	[CN]- (g)	63.973	67.259	± 0.091	kJ/mol	26.01799 ± 0.00080	57-12-5*0
16.0	Isocyanomethane	CH3NC (g)	183.80	177.25	± 0.47	kJ/mol	41.0520 ± 0.0016	593-75-9*0
12.2	Acetylene	HCCH (g)	228.86	228.30	± 0.12	kJ/mol	26.0373 ± 0.0016	74-86-2*0
12.2	Acetylene cation	[HCCH]+ (g)	1328.88	1328.21	± 0.12	kJ/mol	26.0367 ± 0.0016	25641-79-6*0
12.1	Nitrilomethyl	CN (g)	436.72	440.01	± 0.14	kJ/mol	26.01744 ± 0.00080	2074-87-5*0
11.6	Hydrogen cyanide cation	[HCN]+ (g)	1442.53	1442.06	± 0.20	kJ/mol	27.02483 ± 0.00081	12601-62-6*0

Most Influential reactions involving HNC (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
0.780	2778.1	[HNC]- (g) → HNC (g)	Δ_rH°(0 K) = 35.7 ± 2 cm-1	Peterson 2002, est unc
0.668	2777.1	HNC (g) → [HNC]+ (g)	Δ_rH°(0 K) = 12.011 ± 0.010 eV	Gans 2019
0.258	2782.10	HCN (g) → HNC (g)	Δ_rH°(0 K) = 5236 ± 50 cm-1	Nguyen 2015c
0.105	2778.4	[HNC]- (g) → HNC (g)	Δ_rH°(0 K) = 42.41 ± 5 (×1.091) cm-1	Sindelka 2004, est unc
0.100	2778.2	[HNC]- (g) → HNC (g)	Δ_rH°(0 K) = 42.5 ± 5 (×1.114) cm-1	Skurski 2001, est unc
0.099	2823.8	CH3NC (g) + HCN (g) → CH3CN (g) + HNC (g)	Δ_rH°(0 K) = -40.97 ± 1.5 kJ/mol	Klippenstein 2017
0.087	2787.1	[HNC]+ (g) + Xe (g) → Xe+ (g) + HNC (g)	Δ_rH°(300 K) = 0.09 ± 0.02 (×1.384) eV	Hansel 1998
0.084	2783.3	HCN (g) → HNC (g)	Δ_rH°(0 K) = 14.88 ± 0.25 kcal/mol	Karton 2011
0.066	2782.13	HCN (g) → HNC (g)	Δ_rH°(0 K) = 5312.8 ± 60 (×1.646) cm-1	Makhnev 2018
0.064	2782.12	HCN (g) → HNC (g)	Δ_rH°(0 K) = 5201 ± 100 cm-1	Dawes 2009, est unc
0.064	2782.11	HCN (g) → HNC (g)	Δ_rH°(0 K) = 5185.64 ± 100 cm-1	van Mourik 2001, Barber 2002, est unc, Sun 2015
0.062	2776.11	HNC (g) → C (g) + N (g) + H (g)	Δ_rH°(0 K) = 288.27 ± 0.30 kcal/mol	Karton 2011
0.058	2783.14	HCN (g) → HNC (g)	Δ_rH°(0 K) = 14.93 ± 0.30 kcal/mol	Burke 2021
0.056	2823.7	CH3NC (g) + HCN (g) → CH3CN (g) + HNC (g)	Δ_rH°(0 K) = -40.9 ± 2.0 kJ/mol	Vogiatzis 2014, est unc
0.056	2823.6	CH3NC (g) + HCN (g) → CH3CN (g) + HNC (g)	Δ_rH°(0 K) = -40.6 ± 2.0 kJ/mol	Klopper 2010a, est unc
0.053	7943.5	HCCNC (g) + HCN (g) → HCCCN (g) + HNC (g)	Δ_rH°(0 K) = -12.50 ± 0.9 kcal/mol	Ruscic W1RO
0.049	7978.5	CH2CHNC (g) + HCN (g) → CH2CHCN (g) + HNC (g)	Δ_rH°(0 K) = -7.30 ± 0.9 kcal/mol	Ruscic W1RO
0.043	7943.4	HCCNC (g) + HCN (g) → HCCCN (g) + HNC (g)	Δ_rH°(0 K) = -11.50 ± 1.0 kcal/mol	Ruscic CBS-n
0.043	7943.2	HCCNC (g) + HCN (g) → HCCCN (g) + HNC (g)	Δ_rH°(0 K) = -12.14 ± 1.0 kcal/mol	Ruscic G4
0.041	2777.9	HNC (g) → [HNC]+ (g)	Δ_rH°(0 K) = 12.019 ± 0.040 eV	Ruscic W1RO

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.