silicon
- Formula: Si
- Molecular weight: 28.0855
- IUPAC Standard InChI: InChI=1S/Si
- IUPAC Standard InChIKey: XUIMIQQOPSSXEZ-UHFFFAOYSA-N
- CAS Registry Number: 7440-21-3
- Chemical structure:
This structure is also available as a 2d Mol file - Permanent link for this species. Use this link for bookmarking this species for future reference.
- Information on this page:
- Other data available:
- Data at other public NIST sites:
- NIST Atomic Spectra Database - Lines Holdings (on physics web site)
- NIST Atomic Spectra Database - Levels Holdings (on physics web site)
- NIST Atomic Spectra Database - Ground states and ionization energies (on physics web site)
- Computational Chemistry Comparison and Benchmark Database
- Gas Phase Kinetics Database
- X-ray Photoelectron Spectroscopy Database, version 5.0
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Gas phase thermochemistry data
Go To: Top, Condensed phase thermochemistry data, Reaction thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | 108. ± 2. | kcal/mol | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
| ΔfH°gas | 107.55 | kcal/mol | Review | Chase, 1998 | Data last reviewed in March, 1967 |
| Quantity | Value | Units | Method | Reference | Comment |
| S°gas,1 bar | 40.1484 ± 0.001 | cal/mol*K | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
| S°gas,1 bar | 40.148 | cal/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1967 |
Gas Phase Heat Capacity (Shomate Equation)
Cp° = A + B*t + C*t2 + D*t3 +
E/t2
H° − H°298.15= A*t + B*t2/2 +
C*t3/3 + D*t4/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t2/2 + D*t3/3 −
E/(2*t2) + G
Cp = heat capacity (cal/mol*K)
H° = standard enthalpy (kcal/mol)
S° = standard entropy (cal/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 3504.616 - 6000. |
|---|---|
| A | 3.487861 |
| B | 1.248720 |
| C | -0.257858 |
| D | 0.017686 |
| E | 0.551961 |
| F | 107.6330 |
| G | 45.47070 |
| H | 107.5530 |
| Reference | Chase, 1998 |
| Comment | Data last reviewed in March, 1967 |
Condensed phase thermochemistry data
Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°liquid | 11.58 | kcal/mol | Review | Chase, 1998 | Data last reviewed in March, 1967 |
| Quantity | Value | Units | Method | Reference | Comment |
| S°liquid,1 bar | 10.63 | cal/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1967 |
| Quantity | Value | Units | Method | Reference | Comment |
| S°solid,1 bar | 4.50 ± 0.02 | cal/mol*K | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
| Quantity | Value | Units | Method | Reference | Comment |
| S°solid | 4.498 | cal/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1967 |
Liquid Phase Heat Capacity (Shomate Equation)
Cp° = A + B*t + C*t2 + D*t3 +
E/t2
H° − H°298.15= A*t + B*t2/2 +
C*t3/3 + D*t4/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t2/2 + D*t3/3 −
E/(2*t2) + G
Cp = heat capacity (cal/mol*K)
H° = standard enthalpy (kcal/mol)
S° = standard entropy (cal/mol*K)
t = temperature (K) / 1000.
View plot Requires a JavaScript / HTML 5 canvas capable browser.
| Temperature (K) | 1685. - 3504.616 |
|---|---|
| A | 6.500010 |
| B | -2.864021×10-11 |
| C | 1.279461×10-11 |
| D | -1.662670×10-12 |
| E | -1.026381×10-12 |
| F | 9.646662 |
| G | 18.49230 |
| H | 11.58460 |
| Reference | Chase, 1998 |
| Comment | Data last reviewed in March, 1967 |
Solid Phase Heat Capacity (Shomate Equation)
Cp° = A + B*t + C*t2 + D*t3 +
E/t2
H° − H°298.15= A*t + B*t2/2 +
C*t3/3 + D*t4/4 − E/t + F − H
S° = A*ln(t) + B*t + C*t2/2 + D*t3/3 −
E/(2*t2) + G
Cp = heat capacity (cal/mol*K)
H° = standard enthalpy (kcal/mol)
S° = standard entropy (cal/mol*K)
t = temperature (K) / 1000.
View plot Requires a JavaScript / HTML 5 canvas capable browser.
| Temperature (K) | 298. - 1685. |
|---|---|
| A | 5.453440 |
| B | 0.932005 |
| C | -0.019810 |
| D | 0.010065 |
| E | -0.084623 |
| F | -1.951230 |
| G | 10.34380 |
| H | 0.000000 |
| Reference | Chase, 1998 |
| Comment | Data last reviewed in March, 1967 |
Reaction thermochemistry data
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled by: John E. Bartmess
Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.
Individual Reactions
By formula: (Si4- • 4294967295Si) + Si = Si4-
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 98.2 ± 6.9 | kcal/mol | N/A | Nakajima, Taguwa, et al., 1995 | gas phase; Vertical Detachment Energy: 2.15±0.04 eV. |
(CAS Reg. No. 11080-58-3 • 4294967295) +
= CAS Reg. No. 11080-58-3
By formula: (CAS Reg. No. 11080-58-3 • 4294967295Si) + Si = CAS Reg. No. 11080-58-3
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 72.8 ± 3.3 | kcal/mol | N/A | Kawamata, Neigishi, et al., 1996 | gas phase; Vertical Detachment Energy: 0.81±0.05 eV. |
(CAS Reg. No. 106389-62-2 • 4294967295) +
= CAS Reg. No. 106389-62-2
By formula: (CAS Reg. No. 106389-62-2 • 4294967295Si) + Si = CAS Reg. No. 106389-62-2
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 112.2 ± 8.2 | kcal/mol | N/A | Xu, Taylor, et al., 1998 | gas phase |
By formula: (Si3- • 4294967295Si) + Si = Si3-
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 4.6 ± 4.3 | kcal/mol | N/A | Arnold and Neumark, 1994 | gas phase |
(CAS Reg. No. 64236-73-3 • 4294967295) +
= CAS Reg. No. 64236-73-3
By formula: (CAS Reg. No. 64236-73-3 • 4294967295Si) + Si = CAS Reg. No. 64236-73-3
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 124.9 ± 4.0 | kcal/mol | N/A | Nimlos, Harding, et al., 1987 | gas phase |
By formula: (HSi- • 4294967295Si) + Si = HSi-
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔrH° | 83.6 ± 3.2 | kcal/mol | N/A | Kasdan, Herbst, et al., 1975 | gas phase |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Cox, Wagman, et al., 1984
Cox, J.D.; Wagman, D.D.; Medvedev, V.A.,
CODATA Key Values for Thermodynamics, Hemisphere Publishing Corp., New York, 1984, 1. [all data]
Chase, 1998
Chase, M.W., Jr.,
NIST-JANAF Themochemical Tables, Fourth Edition,
J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]
Nakajima, Taguwa, et al., 1995
Nakajima, A.; Taguwa, T.; Nakao, K.; Gomei, M.; Kishi, R.; Iwata, S.; Kaya, K.,
Photoelectron Spectroscopy of silicon-carbon cluster Anions (SinCm-),
J. Chem. Phys., 1995, 103, 6, 2050, https://doi.org/10.1063/1.469731
. [all data]
Kawamata, Neigishi, et al., 1996
Kawamata, H.; Neigishi, Y.; Kishi, R.; Iwata, S.; Nakajima, A.; Kaya, K.,
Photoelectron Spectroscopy of Silicon-Fluorine Binary Cluster Anions (SinFm-),
J. Chem. Phys., 1996, 105, 13, 5369, https://doi.org/10.1063/1.472377
. [all data]
Xu, Taylor, et al., 1998
Xu, C.S.; Taylor, T.R.; Burton, G.R.; Neumark, D.M.,
Vibrationally reserved photoelectron spectroscopy of silicon cluster anions Si-n(-) (n=3-7),
J. Chem. Phys., 1998, 108, 4, 1395-1406, https://doi.org/10.1063/1.475511
. [all data]
Arnold and Neumark, 1994
Arnold, C.C.; Neumark, D.M.,
Threshold Photodetachment Zero-Electron Kinetic Energy Spectroscopy of Si-3(-),
J. Chem. Phys., 1994, 100, 3, 1797, https://doi.org/10.1063/1.466532
. [all data]
Nimlos, Harding, et al., 1987
Nimlos, M.R.; Harding, L.B.; Ellison, G.B.,
The Electronic States of Si2 and Si2- as Revealed by Photoelectron Spectroscopy,
J. Chem. Phys., 1987, 87, 9, 5116, https://doi.org/10.1063/1.453679
. [all data]
Kasdan, Herbst, et al., 1975
Kasdan, A.; Herbst, E.; Lineberger, W.C.,
Laser photoelectron spectrometry of the negative ions of silicon and its hydrides,
J. Chem. Phys., 1975, 62, 541. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, References
- Symbols used in this document:
S°gas,1 bar Entropy of gas at standard conditions (1 bar) S°liquid,1 bar Entropy of liquid at standard conditions (1 bar) S°solid Entropy of solid at standard conditions S°solid,1 bar Entropy of solid at standard conditions (1 bar) ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfH°liquid Enthalpy of formation of liquid at standard conditions ΔrH° Enthalpy of reaction at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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