Selected ATcT [1, 2] enthalpy of formation based on version 1.122o of the Thermochemical Network [3] This version of ATcT results was generated from an expansion of version 1.122h [4] to include the ionization energy of H2O2. [5].
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Species Name |
Formula |
Image |
ΔfH°(0 K) |
ΔfH°(298.15 K) |
Uncertainty |
Units |
Relative Molecular Mass |
ATcT ID |
Cyanooxidanyl | NCO (g) | | 126.89 | 127.37 | ± 0.34 | kJ/mol | 42.01684 ± 0.00086 | 22400-26-6*0 |
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Representative Geometry of NCO (g) |
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spin ON spin OFF |
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Top contributors to the provenance of ΔfH° of NCO (g)The 20 contributors listed below account only for 74.2% of the provenance of ΔfH° of NCO (g). A total of 77 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.
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Contribution (%) | TN ID | Reaction | Measured Quantity | Reference | 16.6 | 3770.1 | HNCO (g) → NCO (g) + H (g)  | ΔrH°(0 K) = 38370 ± 30 cm-1 | Zyrianov 1996 | 16.2 | 3763.4 | NCO (g) → N (g) + CO (g)  | ΔrH°(0 K) = 55.0 ± 0.2 kcal/mol | Cyr 1992, est unc | 7.2 | 3768.1 | NCO (g) + O (g) → CO2 (g) + N (g)  | ΔrH°(0 K) = -70.89 ± 0.3 kcal/mol | Schuurman 2004, est unc | 6.3 | 3769.1 | NCO (g) + OH (g) → CO2 (g) + NH (g)  | ΔrH°(0 K) = -47.42 ± 0.3 kcal/mol | Schuurman 2004, est unc | 5.4 | 3731.7 | HNCO (g) → NH (g) + CO (g)  | ΔrH°(0 K) = 30150 ± 60 cm-1 | Zyrianov 1996 | 2.3 | 3733.8 | HNCO (g) + H2O (g) → CO2 (g) + NH3 (g)  | ΔrH°(0 K) = -18.46 ± 0.3 kcal/mol | Schuurman 2004, est unc | 2.2 | 3726.11 | HNCO (g) → H (g) + N (g) + C (g) + O (g)  | ΔrH°(0 K) = 420.73 ± 0.30 kcal/mol | Karton 2011 | 2.2 | 5523.1 | NH2C(O)NH2 (g) → [NH3]+ (g) + HNCO (g)  | ΔrH°(0 K) = 10.838 ± 0.010 eV | Bodi 2013 | 2.0 | 3731.8 | HNCO (g) → NH (g) + CO (g)  | ΔrH°(0 K) = 30075 ± 25 (×3.914) cm-1 | Sanov 1997 | 1.8 | 3773.1 | HNCO (g) + N (g) → NCO (g) + NH (g)  | ΔrH°(0 K) = 31.39 ± 0.3 kcal/mol | Schuurman 2004, est unc | 1.8 | 3734.6 | HNCO (g) + O (g) → NH (g) + CO2 (g)  | ΔrH°(0 K) = -39.33 ± 0.3 kcal/mol | Schuurman 2004, est unc | 1.5 | 3731.9 | HNCO (g) → NH (g) + CO (g)  | ΔrH°(0 K) = 30060 ± 25 (×4.555) cm-1 | Zyrianov 1999 | 1.3 | 3770.12 | HNCO (g) → NCO (g) + H (g)  | ΔrH°(0 K) = 109.76 ± 0.3 kcal/mol | Schuurman 2004, est unc | 1.3 | 3774.1 | 3 HNCO (g) + N (g) → 3 NCO (g) + NH3 (g)  | ΔrH°(0 K) = 52.38 ± 0.9 kcal/mol | Schuurman 2004, est unc | 1.0 | 3736.11 | HOCN (g) → H (g) + N (g) + C (g) + O (g)  | ΔrH°(0 K) = 395.98 ± 0.30 kcal/mol | Karton 2011 | 1.0 | 3748.11 | HONC (g) → H (g) + N (g) + C (g) + O (g)  | ΔrH°(0 K) = 336.83 ± 0.30 kcal/mol | Karton 2011 | 1.0 | 3742.11 | HCNO (g) → H (g) + N (g) + C (g) + O (g)  | ΔrH°(0 K) = 352.25 ± 0.30 kcal/mol | Karton 2011 | 0.8 | 3731.6 | HNCO (g) → NH (g) + CO (g)  | ΔrH°(0 K) = 30022 ± 100 (×1.509) cm-1 | Brown 1996, Brazier 1986 | 0.8 | 3772.8 | HNCO (g) → [NCO]- (g) + H+ (g)  | ΔrH°(0 K) = 340.17 ± 0.3 kcal/mol | Schuurman 2004, est unc | 0.7 | 3775.1 | 2 HNCO (g) + O (g) → 2 NCO (g) + H2O (g)  | ΔrH°(0 K) = 0.10 ± 0.8 kcal/mol | Schuurman 2004, est unc |
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Top 10 species with enthalpies of formation correlated to the ΔfH° of NCO (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.
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Correlation Coefficent (%) | Species Name | Formula | Image | ΔfH°(0 K) | ΔfH°(298.15 K) | Uncertainty | Units | Relative Molecular Mass | ATcT ID | 65.5 | Isocyanic acid | HNCO (g) | | -116.01 | -119.00 | ± 0.30 | kJ/mol | 43.02478 ± 0.00086 | 75-13-8*0 | 58.0 | Cyanate | [NCO]- (g) | | -221.23 | -221.45 | ± 0.53 | kJ/mol | 42.01739 ± 0.00086 | 661-20-1*0 | 56.4 | Cyanato cation | [NCO]+ (g) | | 1261.45 | 1261.95 | ± 0.58 | kJ/mol | 42.01629 ± 0.00086 | 17247-99-3*0 | 38.1 | Isocyanic acid cation | [HNCO]+ (g) | | 1002.94 | 1000.27 | ± 0.50 | kJ/mol | 43.02423 ± 0.00086 | 444010-28-0*0 | 27.9 | Isofulminic acid | HONC (g) | | 235.26 | 233.56 | ± 0.48 | kJ/mol | 43.02478 ± 0.00086 | 506-85-4*0 | 27.7 | Cyanic acid | HOCN (g) | | -12.31 | -15.03 | ± 0.48 | kJ/mol | 43.02478 ± 0.00086 | 420-05-3*0 | 26.9 | Fulminic acid | HCNO (g) | | 170.81 | 169.35 | ± 0.49 | kJ/mol | 43.02478 ± 0.00086 | 51060-05-0*0 | 15.3 | Oxomethaniminium | [NH2CO]+ (g) | | 695.1 | 688.5 | ± 1.0 | kJ/mol | 44.03217 ± 0.00087 | 59348-22-0*0 | 14.8 | Imidogen | NH (g) | | 358.74 | 358.78 | ± 0.17 | kJ/mol | 15.014680 ± 0.000099 | 13774-92-0*0 | 14.8 | Imidogen | NH (g, triplet) | | 358.74 | 358.78 | ± 0.17 | kJ/mol | 15.014680 ± 0.000099 | 13774-92-0*1 |
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Most Influential reactions involving NCO (g)Please note: The list, which is based on a hat (projection) matrix analysis, is limited to no more than 20 largest influences.
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References
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1
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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]
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2
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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 21st Century.
J. Phys. Conf. Ser. 16, 561-570 (2005)
[DOI: 10.1088/1742-6596/16/1/078]
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3
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B. Ruscic and D. H. Bross, Active Thermochemical Tables (ATcT) values based on ver. 1.122o of the Thermochemical Network (2020); available at ATcT.anl.gov |
4
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Y.-C. Chang, B. Xiong, D. H. Bross, B. Ruscic, and C. Y. Ng,
A Vacuum Ultraviolet laser Pulsed Field Ionization-Photoion Study of Methane (CH4): Determination of the Appearance Energy of Methylium From Methane with Unprecedented Precision and the Resulting Impact on the Bond Dissociation Energies of CH4 and CH4+.
Phys. Chem. Chem. Phys. 19, 9592-9605 (2017)
[DOI: 10.1039/c6cp08200a] (part of 2017 PCCP Hot Articles collection)
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5
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P. B. Changala, T. L. Nguyen, J. H. Baraban, G. B. Ellison, J. F. Stanton, D. H. Bross, and B. Ruscic,
Active Thermochemical Tables: The Adiabatic Ionization Energy of Hydrogen Peroxide.
J. Phys. Chem. A 121, 8799-8806 (2017)
[DOI: 10.1021/acs.jpca.7b06221] (highlighted on the journal cover)
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6
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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]
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Formula
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The aggregate state is given in parentheses following the formula, such as: g - gas-phase, cr - crystal, l - liquid, etc.
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Uncertainties
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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.
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Website Functionality Credits
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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/.
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Acknowledgement
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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.
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