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].

Disilicon cation

Formula: [Si2]+ (g)
CAS RN: 12597-36-3
ATcT ID: 12597-36-3*0
SMILES: [Si][Si+]
InChI: InChI=1S/Si2/c1-2/q+1
InChIKey: MEMLCQNRJARANC-UHFFFAOYSA-N
Hills Formula: Si2+

2D Image:

[Si][Si+]
Aliases: [Si2]+; Disilicon cation; Disilicon ion (1+); Diatomic silicon cation; Diatomic silicon ion (1+); Silicon dimer cation; Silicon dimer ion (1+); 2-Disilynylium-1-yl
Relative Molecular Mass: 56.17045 ± 0.00060

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
1352.31355.9± 2.4kJ/mol

3D Image of [Si2]+ (g)

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Top contributors to the provenance of ΔfH° of [Si2]+ (g)

The 20 contributors listed below account only for 86.3% of the provenance of ΔfH° of [Si2]+ (g).
A total of 25 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
17.18487.4 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.033 ± 0.030 eVRuscic W1RO
14.28440.8 Si2 (g) → 2 Si (g) ΔrH°(0 K) = 74.96 ± 0.30 kcal/molFeller 2008
13.28441.6 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 7.905 ± 0.040 eVRuscic W1RO
6.48487.2 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.001 ± 0.049 eVRuscic G4
4.58473.1 SiC (g) → [SiC]+ (g) ΔrH°(0 K) = 8.978 ± 0.010 eVGans 2023
4.08487.1 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.015 ± 0.062 eVRuscic G3X
3.98441.4 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 7.924 ± 0.073 eVRuscic G4
3.58491.1 Si (cr,l) + 2 F2 (g) → SiF4 (g) ΔrH°(298.15 K) = -385.98 ± 0.19 kcal/molWise 1963, Wise 1963, Wise 1962
2.88440.7 Si2 (g) → 2 Si (g) ΔrH°(0 K) = 74.2 ± 0.4 (×1.682) kcal/molFeller 1999a, Feller 1999a
2.48441.3 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 7.895 ± 0.093 eVRuscic G3X
1.88441.5 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 7.819 ± 0.099 (×1.091) eVRuscic CBS-n
1.68487.3 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.140 ± 0.066 (×1.477) eVRuscic CBS-n
1.58434.2 Si (cr,l) → Si (g) ΔrG°(1525 K) = 231.1 ± 2.0 kJ/molBatdorf 1959, 3rd Law
1.58487.5 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.03 ± 0.10 eVBruna 1981, est unc
1.48584.1 SiH3SiH3 (g) → 2 Si (cr,l) + 3 H2 (g) ΔrH°(298.15 K) = -19.1 ± 0.6 (×1.61) kcal/molGunn 1961, est unc
1.4546.1 SiF4 (g) + 2 H2O (cr,l) → Si (cr,l) O2 (g) + 4 HF (aq, 5 H2O) ΔrH°(298.15 K) = 899.77 ± 1.20 kJ/molPaulechka 2020, Vorobev 1960, Hummel 1959, Johnson 1987, Good 1964, Good 1964, Johnson 1973
1.38548.1 SiH4 (g) → Si (cr,l) + 2 H2 (g) ΔrH°(298.15 K) = -8.3 ± 0.5 kcal/molGunn 1961, Gurvich TPIS, est unc
1.08469.6 SiO2 (cr,l) Si (cr,l) → 2 SiO (g) ΔrG°(1618 K) = 37.94 ± 0.29 kcal/molRamstad 1961, 3rd Law, Gurvich TPIS
0.98491.3 Si (cr,l) + 2 F2 (g) → SiF4 (g) ΔrH°(298.15 K) = -1615.78 ± 0.46 (×3.292) kJ/molJohnson 1986, Johnson 1986
0.98441.1 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 8.00 ± 0.15 eVWinstead 1995, Winstead 1995a, est unc

Top 10 species with enthalpies of formation correlated to the ΔfH° of [Si2]+ (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 Image    ΔfH°(0 K)    ΔfH°(298.15 K) Uncertainty Units Relative
Molecular
Mass
ATcT ID
64.0 DisiliconSi2 (g)[Si][Si]587.5591.3± 1.6kJ/mol56.17100 ±
0.00060
12597-35-2*0
57.6 Disilicon anion[Si2]- (g)[Si][Si-]375.1379.0± 1.7kJ/mol56.17155 ±
0.00060
64236-73-3*0
45.7 Silicon atom dication[Si]+2 (g)[Si++]2814.002816.98± 0.56kJ/mol28.08440 ±
0.00030
14175-55-4*0
45.7 Silicon cationSi+ (g)[Si+]1236.861240.99± 0.56kJ/mol28.08495 ±
0.00030
14067-07-3*0
45.7 Silicon anionSi- (g)[Si-]316.28319.26± 0.56kJ/mol28.08605 ±
0.00030
14337-02-1*0
45.7 SiliconSi (g)[Si]450.34454.68± 0.56kJ/mol28.08550 ±
0.00030
7440-21-3*0
45.7 Silicon atom trication[Si]+3 (g)[Si+3]6045.586048.56± 0.56kJ/mol28.08385 ±
0.00030
14175-56-5*0
45.7 Silicon atom tetracation[Si]+4 (g)[Si+4]10401.1010404.08± 0.56kJ/mol28.08331 ±
0.00030
22537-24-2*0
39.2 DisilaneSiH3SiH3 (g)[SiH3][SiH3]92.075.9± 1.3kJ/mol62.21864 ±
0.00073
1590-87-0*0
39.0 SilaneSiH4 (g)[SiH4]42.6633.04± 0.63kJ/mol32.11726 ±
0.00041
7803-62-5*0

Most Influential reactions involving [Si2]+ (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
0.3738487.4 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.033 ± 0.030 eVRuscic W1RO
0.2258441.6 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 7.905 ± 0.040 eVRuscic W1RO
0.1398487.2 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.001 ± 0.049 eVRuscic G4
0.0878487.1 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.015 ± 0.062 eVRuscic G3X
0.0678441.4 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 7.924 ± 0.073 eVRuscic G4
0.0418441.3 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 7.895 ± 0.093 eVRuscic G3X
0.0358487.3 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.140 ± 0.066 (×1.477) eVRuscic CBS-n
0.0338487.5 SiC (g) [Si2]+ (g) → [SiC]+ (g) Si2 (g) ΔrH°(0 K) = 1.03 ± 0.10 eVBruna 1981, est unc
0.0308441.5 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 7.819 ± 0.099 (×1.091) eVRuscic CBS-n
0.0168441.1 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 8.00 ± 0.15 eVWinstead 1995, Winstead 1995a, est unc
0.0058441.2 Si2 (g) → [Si2]+ (g) ΔrH°(0 K) = 7.72 ± 0.25 eVFuke 1993, Winstead 1995, Winstead 1995a


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 21st 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.