Selected ATcT [1, 2] enthalpy of formation based on version 1.124 of the Thermochemical Network [3]

This version of ATcT results was generated by additional expansion of version 1.122x [4] to include additional information relevant to the study of thermophysical and thermochemical properties of CH2 and CH3 using nonrigid rotor anharmonic oscillator (NRRAO) partition functions [5], the development and benchmarking of a state-of-the-art computational approach that aims to reproduce total atomization energies of small molecules within 10–15 cm-1 [6], as well as the study of the reversible reaction C2H3 + H2 ⇌ C2H4 + H ⇌ C2H5 [7]

Dioxosilane

Formula: SiO2 (cr, cristobalite)
CAS RN: 7631-86-9
ATcT ID: 7631-86-9*510
SMILES: O=[Si]=O
InChI: InChI=1S/O2Si/c1-3-2
InChIKey: VYPSYNLAJGMNEJ-UHFFFAOYSA-N
Hills Formula: O2Si1

2D Image:

O=[Si]=O
Aliases: SiO2; Dioxosilane; Silicon dioxide; Quartz; alpha-Quartz; beta-Quartz; Cristobalite; Tridymite; Aventurine; Silica; Silicon oxide; Silicon (IV) oxide; 14808-60-7; 14464-46-1; 99493-55-7; 15468-32-3; 60676-86-0
Relative Molecular Mass: 60.08430 ± 0.00067

   ΔfH°(0 K)   ΔfH°(298.15 K)UncertaintyUnits
-904.05-908.91± 0.69kJ/mol

Top contributors to the provenance of ΔfH° of SiO2 (cr, cristobalite)

The 16 contributors listed below account for 90.0% of the provenance of ΔfH° of SiO2 (cr, cristobalite).

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
19.07425.1 Si (cr,l) + 2 F2 (g) → SiF4 (g) ΔrH°(298.15 K) = -385.98 ± 0.19 kcal/molWise 1963, Wise 1963, Wise 1962
16.2525.1 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
11.67386.1 Si (cr,l) O2 (g) → SiO2 (cr,l) ΔrH°(298.15 K) = -217.58 ± 0.35 (×1.164) kcal/molGood 1964, Good 1964, Good 1962, King 1951
7.1524.1 SiF4 (g) + 2 H2O (cr,l) → SiO2 (cr, quartz) + 4 HF (aq, 5 H2O) ΔrH°(298.15 K) = -11.11 ± 0.37 kJ/molPaulechka 2020, Vorobev 1960, Hummel 1959, Johnson 1987, Good 1964, Good 1964, Kilday 1973, Kilday 1973, Johnson 1973
5.67388.3 SiO2 (cr, quartz) → SiO2 (cr, cristobalite) ΔrH°(347.85 K) = 0.63 ± 0.10 kcal/molKracek 1953, est unc
5.57427.1 SiO2 (vitr) + 2 F2 (g) → SiF4 (g) O2 (g) ΔrH°(298.15 K) = -170.04 ± 0.25 kcal/molWise 1963, Wise 1963
5.47425.3 Si (cr,l) + 2 F2 (g) → SiF4 (g) ΔrH°(298.15 K) = -1615.78 ± 0.46 (×3.221) kJ/molJohnson 1986, Johnson 1986
4.47391.2 SiO2 (cr, cristobalite) → SiO2 (vitr) ΔrH°(347.85 K) = 1.55 ± 0.10 kcal/molKracek 1953, est unc
2.9523.2 H2O (cr,l) F2 (g) → 2 HF (aq, 5 H2O) + 1/2 O2 (g) ΔrH°(298.15 K) = -356.66 ± 0.40 kJ/molPaulechka 2020, Johnson 1987, Vorobev 1960, Hummel 1959, Johnson 1973
2.77426.1 SiO2 (cr,l) + 2 F2 (g) → SiF4 (g) O2 (g) ΔrH°(298.15 K) = -168.26 ± 0.28 (×1.215) kcal/molWise 1963, Wise 1963
2.47388.2 SiO2 (cr, quartz) → SiO2 (cr, cristobalite) ΔrH°(970 K) = 0.45 ± 0.15 kcal/molHolm 1967
1.5524.2 SiF4 (g) + 2 H2O (cr,l) → SiO2 (cr, quartz) + 4 HF (aq, 5 H2O) ΔrH°(298.15 K) = -11.95 ± 0.25 (×3.221) kJ/molPaulechka 2020, Vorobev 1960, Hummel 1959, Johnson 1987, Good 1964, Good 1964, Johnson 1982, Johnson 1973
1.57368.2 Si (cr,l) → Si (g) ΔrG°(1525 K) = 231.1 ± 2.0 kJ/molBatdorf 1959, 3rd Law
1.37467.1 SiH3SiH3 (g) → 2 Si (cr,l) + 3 H2 (g) ΔrH°(298.15 K) = -19.1 ± 0.6 (×1.576) kcal/molGunn 1961, est unc
1.27431.1 SiH4 (g) → Si (cr,l) + 2 H2 (g) ΔrH°(298.15 K) = -8.3 ± 0.5 kcal/molGunn 1961, Gurvich TPIS, est unc
1.07391.1 SiO2 (cr, cristobalite) → SiO2 (vitr) ΔrH°(970 K) = 0.95 ± 0.15 (×1.354) kcal/molHolm 1967

Top 10 species with enthalpies of formation correlated to the ΔfH° of SiO2 (cr, cristobalite)

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
92.2 DioxosilaneSiO2 (cr, quartz)O=[Si]=O-906.75-911.73± 0.64kJ/mol60.08430 ±
0.00067
7631-86-9*505
92.2 DioxosilaneSiO2 (cr,l)O=[Si]=O-906.75-911.73± 0.64kJ/mol60.08430 ±
0.00067
7631-86-9*500
92.0 DioxosilaneSiO2 (vitr)O=[Si]=O-826.30-902.23± 0.65kJ/mol60.08430 ±
0.00067
7631-86-9*520
65.7 TetrafluorosilaneSiF4 (g)[Si](F)(F)(F)F-1608.81-1614.32± 0.53kJ/mol104.07911 ±
0.00030
7783-61-1*0
52.3 OxosilyleneSiO (g)[Si]=O-98.36-97.20± 0.54kJ/mol44.08490 ±
0.00042
10097-28-6*0
43.0 DioxosilaneSiO2 (cr, tridymite)O=[Si]=O-901.5-906.3± 1.4kJ/mol60.08430 ±
0.00067
7631-86-9*515
41.9 SiliconSi (g)[Si]450.37454.70± 0.59kJ/mol28.08550 ±
0.00030
7440-21-3*0
41.9 Silicon anionSi- (g)[Si-]316.30319.28± 0.59kJ/mol28.08605 ±
0.00030
14337-02-1*0
41.9 Silicon cationSi+ (g)[Si+]1236.891241.01± 0.59kJ/mol28.08495 ±
0.00030
14067-07-3*0
41.9 Silicon atom dication[Si]+2 (g)[Si++]2814.022817.00± 0.59kJ/mol28.08440 ±
0.00030
14175-55-4*0

Most Influential reactions involving SiO2 (cr, cristobalite)

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
0.4077391.2 SiO2 (cr, cristobalite) → SiO2 (vitr) ΔrH°(347.85 K) = 1.55 ± 0.10 kcal/molKracek 1953, est unc
0.3957388.3 SiO2 (cr, quartz) → SiO2 (cr, cristobalite) ΔrH°(347.85 K) = 0.63 ± 0.10 kcal/molKracek 1953, est unc
0.1757388.2 SiO2 (cr, quartz) → SiO2 (cr, cristobalite) ΔrH°(970 K) = 0.45 ± 0.15 kcal/molHolm 1967
0.0987391.1 SiO2 (cr, cristobalite) → SiO2 (vitr) ΔrH°(970 K) = 0.95 ± 0.15 (×1.354) kcal/molHolm 1967
0.0147388.4 SiO2 (cr, quartz) → SiO2 (cr, cristobalite) ΔrH°(298.15 K) = 0.93 ± 0.52 kcal/molHumphrey 1952, Humphrey 1952a
0.0027394.1 SiO2 (cr, cristobalite) → SiO2 (g) ΔrG°(1850 K) = 261.4 ± 10.9 (×4) kJ/molPorter 1955, 3rd Law
0.0007402.2 SiO2 (cr, cristobalite) → SiO (g) + 1/2 O2 (g) ΔrG°(1956 K) = 317 ± 20 kJ/molShchedrin 1977, 3rd Law, Gurvich TPIS
0.0007402.1 SiO2 (cr, cristobalite) → SiO (g) + 1/2 O2 (g) ΔrG°(1850 K) = 260.5 ± 70 (×1.067) kJ/molPorter 1955, 3rd Law, Gurvich TPIS


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. 1.124 of the Thermochemical Network, Argonne National Laboratory, Lemont, Illinois 2022; available at ATcT.anl.gov
[DOI: 10.17038/CSE/1885923]
4   Y. Ren, L. Zhou, A. Mellouki, V. Daële, M. Idir, S. S. Brown, B. Ruscic, Robert S. Paton, M. R. McGillen, and A. R. Ravishankara,
Reactions of NO3 with Aromatic Aldehydes: Gas-Phase Kinetics and Insights into the Mechanism of the Reaction.
Atmos. Chem. Phys. 21, 13537-13551 (2021) [DOI: 10.5194/acp2021-228]
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   T. L. Nguyen, D. H. Bross, B. Ruscic, G. B. Ellison, and J. F. Stanton,
Mechanism, Thermochemistry, and Kinetics of the Reversible Reactions: C2H3 + H2 ⇌ C2H4 + H ⇌ C2H5.
Faraday Discuss. , (Advance Article) (2022) [DOI: 10.1039/D1FD00124H]
8   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]
9   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 [8,9]).
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.