Selected ATcT [1, 2] enthalpy of formation based on version 1.130 of the Thermochemical Network [3]

This version of ATcT results[4] was generated by additional expansion of version 1.128 [5,6] to include with the calculations provided in reference [4].

Isocyanogen

Formula: CNCN (g)

CAS RN: 83951-85-3

ATcT ID: 83951-85-3*0

SMILES: [C-]#[N+]C#N

InChI: InChI=1S/C2N2/c1-4-2-3

InChIKey: NHFDIUPJVYYTLG-UHFFFAOYSA-N

Hills Formula: C2N2

2D Image:

Aliases: CNCN; Isocyanogen; Cyanic isocyanide; Cyanogen cyanide; Cyanoisocyanide; NCNC

Relative Molecular Mass: 52.0349 ± 0.0016

Δ_fH°(0 K)	Δ_fH°(298.15 K)	Uncertainty	Units
412.1	414.4	± 1.3	kJ/mol

3D Image of CNCN (g)

spin ON spin OFF

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

The 20 contributors listed below account only for 83.3% of the provenance of Δ_fH° of CNCN (g).
A total of 28 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
31.2	5293.12	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 105.94 ± 2.0 (×1.022) kJ/mol	Klippenstein 2017
5.1	5293.8	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 24.93 ± 1.2 kcal/mol	Ruscic W1RO
4.8	5294.4	[NCCN]+ (g) → [CNCN]+ (g)	Δ_rH°(0 K) = 13.80 ± 1.2 kcal/mol	Ruscic W1RO
4.4	5293.7	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 24.66 ± 1.3 kcal/mol	Ruscic CBS-n, Petrie 1998
4.4	5293.4	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 24.63 ± 1.3 kcal/mol	Ruscic G4
4.1	5294.2	[NCCN]+ (g) → [CNCN]+ (g)	Δ_rH°(0 K) = 12.19 ± 1.3 kcal/mol	Ruscic G4
3.8	5293.3	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 25.19 ± 1.4 kcal/mol	Ruscic G3X
3.5	5294.1	[NCCN]+ (g) → [CNCN]+ (g)	Δ_rH°(0 K) = 12.88 ± 1.4 kcal/mol	Ruscic G3X
3.3	5293.11	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 23.66 ± 1.50 kcal/mol	Ding 2000, est unc
3.3	5293.10	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 25.35 ± 1.50 kcal/mol	Ding 1998, est unc
2.9	5293.6	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 23.99 ± 1.6 kcal/mol	Ruscic CBS-n
2.7	5294.3	[NCCN]+ (g) → [CNCN]+ (g)	Δ_rH°(0 K) = 12.67 ± 1.6 kcal/mol	Ruscic CBS-n
1.3	5303.8	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 47.92 ± 1.2 kcal/mol	Ruscic W1RO
1.3	5293.9	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 100.24 ± 10. kJ/mol	Botschwina 1990, note unc2
1.2	5302.8	NCCN (g) → CNNC (g)	Δ_rH°(0 K) = 72.85 ± 1.2 kcal/mol	Ruscic W1RO
1.1	5303.7	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 47.52 ± 1.3 kcal/mol	Ruscic CBS-n
1.1	5303.4	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 47.47 ± 1.3 kcal/mol	Ruscic G4
1.0	5302.7	NCCN (g) → CNNC (g)	Δ_rH°(0 K) = 72.19 ± 1.3 kcal/mol	Ruscic CBS-n
1.0	5302.4	NCCN (g) → CNNC (g)	Δ_rH°(0 K) = 72.09 ± 1.3 kcal/mol	Ruscic G4
1.0	5279.12	NCCN (g) → 2 N (g) + 2 C (g)	Δ_rH°(0 K) = 491.50 ± 0.30 kcal/mol	Karton 2008

Top 10 species with enthalpies of formation correlated to the Δ_fH° of CNCN (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
93.4	Isocyanogen cation	[CNCN]+ (g)	1654.1	1656.5	± 1.4	kJ/mol	52.0343 ± 0.0016	133415-63-1*0
40.8	Diisocyanogen	CNNC (g)	610.9	613.2	± 1.7	kJ/mol	52.0349 ± 0.0016	78800-21-2*0
39.3	Isocyanogen anion	[CNCN]- (g)	386.6	388.7	± 3.3	kJ/mol	52.0354 ± 0.0016	83951-85-30
32.0	Cyanogen	NCCN (g)	308.18	310.12	± 0.41	kJ/mol	52.0349 ± 0.0016	460-19-5*0
31.6	Cyanogen	NCCN (cr,l)	273.94	289.19	± 0.42	kJ/mol	52.0349 ± 0.0016	460-19-5*500
31.4	Cyanogen cation	[NCCN]+ (g)	1598.24	1600.46	± 0.42	kJ/mol	52.0343 ± 0.0016	37354-81-7*0
22.8	Diisocyanogen cation	[CNNC]+ (g, cis)	1838.6	1842.6	± 3.1	kJ/mol	52.0343 ± 0.0016	78800-21-22
21.6	Diisocyanogen cation	[CNNC]+ (g, trans)	1825.3	1828.1	± 3.2	kJ/mol	52.0343 ± 0.0016	78800-21-21
21.6	Diisocyanogen cation	[CNNC]+ (g)	1825.3	1828.5	± 3.2	kJ/mol	52.0343 ± 0.0016	78800-21-20
19.2	Diisocyanogen anion	[CNNC]- (g)	456.8	462.5	± 3.6	kJ/mol	52.0354 ± 0.0016	78800-22-30

Most Influential reactions involving CNCN (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
0.962	5288.1	CNCN (g) → [CNCN]+ (g)	Δ_rH°(0 K) = 12.873 ± 0.005 eV	Grabandt 1989, Cederbaum 1989
0.381	5289.8	[CNCN]- (g) → CNCN (g)	Δ_rH°(0 K) = 0.280 ± 0.050 eV	Ruscic W1RO
0.348	5293.12	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 105.94 ± 2.0 (×1.022) kJ/mol	Klippenstein 2017
0.256	5289.4	[CNCN]- (g) → CNCN (g)	Δ_rH°(0 K) = 0.262 ± 0.061 eV	Ruscic G4
0.132	5289.3	[CNCN]- (g) → CNCN (g)	Δ_rH°(0 K) = 0.218 ± 0.085 eV	Ruscic G3X
0.117	5289.7	[CNCN]- (g) → CNCN (g)	Δ_rH°(0 K) = 0.261 ± 0.090 eV	Ruscic CBS-n
0.112	5289.6	[CNCN]- (g) → CNCN (g)	Δ_rH°(0 K) = 0.271 ± 0.092 eV	Ruscic CBS-n
0.107	5303.8	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 47.92 ± 1.2 kcal/mol	Ruscic W1RO
0.091	5303.4	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 47.47 ± 1.3 kcal/mol	Ruscic G4
0.091	5303.7	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 47.52 ± 1.3 kcal/mol	Ruscic CBS-n
0.079	5303.3	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 48.38 ± 1.4 kcal/mol	Ruscic G3X
0.069	5303.10	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 47.17 ± 1.50 kcal/mol	Ding 2000, est unc
0.069	5303.9	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 47.50 ± 1.50 kcal/mol	Ding 1998, est unc
0.060	5303.6	CNCN (g) → CNNC (g)	Δ_rH°(0 K) = 47.22 ± 1.6 kcal/mol	Ruscic CBS-n
0.057	5293.8	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 24.93 ± 1.2 kcal/mol	Ruscic W1RO
0.049	5293.7	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 24.66 ± 1.3 kcal/mol	Ruscic CBS-n, Petrie 1998
0.049	5293.4	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 24.63 ± 1.3 kcal/mol	Ruscic G4
0.042	5293.3	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 25.19 ± 1.4 kcal/mol	Ruscic G3X
0.036	5293.11	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 23.66 ± 1.50 kcal/mol	Ding 2000, est unc
0.036	5293.10	NCCN (g) → CNCN (g)	Δ_rH°(0 K) = 25.35 ± 1.50 kcal/mol	Ding 1998, est unc

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. 1.130 of the Thermochemical Network. Argonne National Laboratory, Lemont, Illinois 2023; available at ATcT.anl.gov [DOI: 10.17038/CSE/1997229]
4		N. Genossar, P. B. Changala, B. Gans, J.-C. Loison, S. Hartweg, M.-A. Martin-Drumel, G. A. Garcia, J. F. Stanton, B. Ruscic, and J. H. Baraban Ring-Opening Dynamics of the Cyclopropyl Radical and Cation: the Transition State Nature of the Cyclopropyl Cation J. Am. Chem. Soc. 144, 18518-18525 (2022) [DOI: 10.1021/jacs.2c07740]
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		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]
8		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 [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.