Selected ATcT [1, 2] enthalpy of formation based on version 1.148 of the Thermochemical Network [3]

This version of ATcT results[3] was generated by additional expansion of version 1.140 to include species relevant to a recent study of the role of atmospheric methanediol[4].

Cyanogen

Formula: NCCN (cr,l)

CAS RN: 460-19-5

ATcT ID: 460-19-5*500

SMILES: N#CC#N

InChI: InChI=1S/C2N2/c3-1-2-4

InChIKey: JMANVNJQNLATNU-UHFFFAOYSA-N

Hills Formula: C2N2

2D Image:

Aliases: NCCN; Cyanogen; Oxalonitrile; Ethanedinitrile; Carbon nitride; Dicyan; Dicyanogen; Nitriloacetonitrile; Oxalic acid dinitrile; Oxalyl cyanide; C2N2; UN 1026; RCRA P031; Prussite; Oxalic nitrile; Cyanogen gas; (CN)2; (NC)2

Relative Molecular Mass: 52.0349 ± 0.0016

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
273.95	289.20	± 0.42	kJ/mol

Top contributors to the provenance of Δ_fH° of NCCN (cr,l)

The 20 contributors listed below account only for 75.8% of the provenance of Δ_fH° of NCCN (cr,l).
A total of 67 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
9.5	5416.12	NCCN (g) → 2 N (g) + 2 C (g)	Δ_rH°(0 K) = 491.50 ± 0.30 kcal/mol	Karton 2008
8.0	2688.12	2 HCN (g) → NCCN (g) + H2 (g)	Δ_rH°(0 K) = 11.51 ± 0.30 kcal/mol	Martin 2006, Karton 2006
5.8	2688.11	2 HCN (g) → NCCN (g) + H2 (g)	Δ_rH°(0 K) = 11.62 ± 0.35 kcal/mol	Martin 2006, Karton 2006
5.3	5416.11	NCCN (g) → 2 N (g) + 2 C (g)	Δ_rH°(0 K) = 491.17 ± 0.40 kcal/mol	Martin 2006
4.9	5422.2	NCCN (g) + 2 O2 (g) → 2 CO2 (g) + N2 (g)	Δ_rH°(298.15 K) = -1095.97 ± 1.80 kJ/mol	Knowlton 1951
4.5	2688.10	2 HCN (g) → NCCN (g) + H2 (g)	Δ_rH°(0 K) = 11.76 ± 0.4 kcal/mol	Martin 2006, Karton 2006
4.5	2689.11	2 HCN (g) → NCCN (g) + 2 H (g)	Δ_rH°(0 K) = 114.91 ± 0.40 kcal/mol	Martin 2006, Karton 2006
3.9	2774.3	NCCN (g) → 2 CN (g)	Δ_rH°(0 K) = 134.76 ± 0.40 kcal/mol	Martin 2006
3.9	2774.4	NCCN (g) → 2 CN (g)	Δ_rH°(0 K) = 134.96 ± 0.40 kcal/mol	Martin 2006
3.5	2689.12	2 HCN (g) → NCCN (g) + 2 H (g)	Δ_rH°(0 K) = 114.80 ± 0.45 kcal/mol	Martin 2006, Karton 2006
3.5	2773.1	NCCN (g) → 2 CN (g)	Δ_rH°(0 K) = 47108 ± 50 (×2.954) cm-1	Huang 1992
2.7	5416.10	NCCN (g) → 2 N (g) + 2 C (g)	Δ_rH°(0 K) = 491.12 ± 0.56 kcal/mol	Martin 2006
2.7	2774.14	NCCN (g) → 2 CN (g)	Δ_rH°(0 K) = 565.25 ± 2.0 kJ/mol	Klippenstein 2017
2.3	5416.14	NCCN (g) → 2 N (g) + 2 C (g)	Δ_rH°(0 K) = 491.36 ± 0.6 kcal/mol	Feller 2008
2.3	2689.10	2 HCN (g) → NCCN (g) + 2 H (g)	Δ_rH°(0 K) = 115.04 ± 0.56 kcal/mol	Martin 2006, Karton 2006
1.9	2774.2	NCCN (g) → 2 CN (g)	Δ_rH°(0 K) = 134.70 ± 0.56 kcal/mol	Martin 2006
1.9	5423.1	NCCN (cr,l) → NCCN (g)	Δ_rH°(252.00 K) = 5.576 ± 0.018 kcal/mol	Ruehrwein 1939
1.7	2774.5	NCCN (g) → 2 CN (g)	Δ_rH°(0 K) = 135.14 ± 0.6 kcal/mol	Feller 2008
1.3	5422.1	NCCN (g) + 2 O2 (g) → 2 CO2 (g) + N2 (g)	Δ_rH°(298.15 K) = -261.40 ± 0.20 (×4.088) kcal/mol	Wartenberg 1933, as quoted by Cox 1970
0.8	6624.8	HCCCCH (g) + 2 HCN (g) → NCCN (g) + 2 HCCH (g)	Δ_rH°(0 K) = 11.48 ± 0.9 kcal/mol	Ruscic W1RO

Top 10 species with enthalpies of formation correlated to the Δ_fH° of NCCN (cr,l)

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
98.7	Cyanogen	NCCN (g)	308.19	310.14	± 0.41	kJ/mol	52.0349 ± 0.0016	460-19-5*0
96.1	Cyanogen cation	[NCCN]+ (g)	1598.26	1600.47	± 0.42	kJ/mol	52.0343 ± 0.0016	37354-81-7*0
31.5	Isocyanogen	CNCN (g)	412.1	414.4	± 1.3	kJ/mol	52.0349 ± 0.0016	83951-85-3*0
30.2	Isocyanogen cation	[CNCN]+ (g)	1654.2	1656.5	± 1.4	kJ/mol	52.0343 ± 0.0016	133415-63-1*0
27.1	Nitrilomethyl	CN (g)	436.74	440.03	± 0.14	kJ/mol	26.01744 ± 0.00080	2074-87-5*0
26.7	Hydrogen cyanide	HCN (g)	129.685	129.301	± 0.087	kJ/mol	27.02538 ± 0.00081	74-90-8*0
26.7	Hydrogen cyanide anion	[HCN]- (g)	129.534	129.055	± 0.087	kJ/mol	27.02593 ± 0.00081	12334-27-9*0
25.6	Cyanide	[CN]- (g)	63.980	67.266	± 0.091	kJ/mol	26.01799 ± 0.00080	57-12-5*0
23.8	Diisocyanogen	CNNC (g)	610.9	613.2	± 1.7	kJ/mol	52.0349 ± 0.0016	78800-21-2*0
18.2	Cyanoacetylene	HCCCN (g)	372.21	373.95	± 0.58	kJ/mol	51.0468 ± 0.0024	1070-71-9*0

Most Influential reactions involving NCCN (cr,l)

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
0.765	5423.1	NCCN (cr,l) → NCCN (g)	Δ_rH°(252.00 K) = 5.576 ± 0.018 kcal/mol	Ruehrwein 1939
0.124	5423.3	NCCN (cr,l) → NCCN (g)	Δ_rH°(298.15 K) = 4.96 ± 0.02 (×2.229) kcal/mol	Ruehrwein 1939, as quoted by Pedley 1986
0.099	5423.2	NCCN (cr,l) → NCCN (g)	Δ_rH°(252.00 K) = 5.624 ± 0.050 kcal/mol	Ruehrwein 1939
0.010	5423.4	NCCN (cr,l) → NCCN (g)	Δ_rH°(298.15 K) = 20.80 ± 0.65 kJ/mol	Majer 1985

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. 1.148 of the Thermochemical Network (2023); available at ATcT.anl.gov
4		T. L. Nguyen, J. Peeters, J.-F. Müller, A. Perera, D. H. Bross, B. Ruscic, and J. F. Stanton, Methanediol from Cloud-Processed Formaldehyde is Only a Minor Source of Atmospheric Formic Acid Natl. Acad. Sci. 120, e2304650120/1-8 (2023) [DOI: 10.1073/pnas.2304650120]
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.