silicon carbide
- Formula: CSi
- Molecular weight: 40.0962
- CAS Registry Number: 409-21-2
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Gas phase thermochemistry data
Go To: Top, Condensed phase thermochemistry data, Constants of diatomic molecules, 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 | 719.65 | kJ/mol | Review | Chase, 1998 | Data last reviewed in March, 1966 |
| Quantity | Value | Units | Method | Reference | Comment |
| S°gas,1 bar | 213.02 | J/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1966 |
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 (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 298. to 1000. | 1000. to 6000. |
|---|---|---|
| A | 60.32180 | 33.36570 |
| B | 4.423940 | 4.437140 |
| C | -61.79470 | -0.865113 |
| D | 39.06140 | 0.057726 |
| E | -1.675991 | 3.073291 |
| F | 696.3070 | 717.4580 |
| G | 277.6700 | 262.5750 |
| H | 719.6480 | 719.6480 |
| Reference | Chase, 1998 | Chase, 1998 |
| Comment | Data last reviewed in March, 1966 | Data last reviewed in March, 1966 |
Condensed phase thermochemistry data
Go To: Top, Gas phase thermochemistry data, Constants of diatomic molecules, 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°solid | -71.55 | kJ/mol | Review | Chase, 1998 | α phase; Data last reviewed in March, 1966 |
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 (J/mol*K)
H° = standard enthalpy (kJ/mol)
S° = standard entropy (J/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 298. to 1000. | 1000. to 4000. | 298. to 1100. | 1100. to 4000. |
|---|---|---|---|---|
| A | 20.55859 | 46.90222 | 20.50009 | 48.22227 |
| B | 64.57962 | 5.845968 | 63.37170 | 5.004148 |
| C | -52.98827 | -1.085410 | -49.54023 | -1.037594 |
| D | 16.95813 | 0.093021 | 14.82801 | 0.086339 |
| E | -0.781847 | -3.448876 | -0.759969 | -3.912333 |
| F | -82.73693 | -95.46716 | -84.29337 | -98.46542 |
| G | 19.90848 | 56.97520 | 20.30926 | 57.76221 |
| H | -71.54598 | -71.54598 | -73.22000 | -73.22000 |
| Reference | Chase, 1998 | Chase, 1998 | Chase, 1998 | Chase, 1998 |
| Comment | α phase; Data last reviewed in March, 1966 | α phase; Data last reviewed in March, 1966 | β phase; Data last reviewed in March, 1966 | β phase; Data last reviewed in March, 1966 |
Constants of diatomic molecules
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: Klaus P. Huber and Gerhard H. Herzberg
Data collected through August, 1977
| Symbol | Meaning |
|---|---|
| State | electronic state and / or symmetry symbol |
| Te | minimum electronic energy (cm-1) |
| ωe | vibrational constant – first term (cm-1) |
| ωexe | vibrational constant – second term (cm-1) |
| ωeye | vibrational constant – third term (cm-1) |
| Be | rotational constant in equilibrium position (cm-1) |
| αe | rotational constant – first term (cm-1) |
| γe | rotation-vibration interaction constant (cm-1) |
| De | centrifugal distortion constant (cm-1) |
| βe | rotational constant – first term, centrifugal force (cm-1) |
| re | internuclear distance (Å) |
| Trans. | observed transition(s) corresponding to electronic state |
| ν00 | position of 0-0 band (units noted in table) |
| State | Te | ωe | ωexe | ωeye | Be | αe | γe | De | βe | re | Trans. | ν00 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No spectra have been conclusively assigned to SiC. The following constants are from ab initio calculations Lutz and Ryan, 1974: | ||||||||||||
| a 1Σ+ | (6628) | (1018) | (0.695) | (1.70) | ||||||||
| * 3Σ- | (5597) | (606) | (0.556) | (1.90) | ||||||||
| * 3Πi | 0 1 | (983) | (0.606) | (1.82) 1 | ||||||||
Notes
| 1 | Lovas, 1974 assumes a 1Σ ground state and estimates re = 1.65 from an extrapolation to SiC of the shortening of Si-O, Si-N single bonds in the corresponding diatomic molecules. |
| 2 | Thermochemical value (mass-spectrometry) Verhaegen, Stafford, et al., 1964. |
References
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Constants of diatomic molecules, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Chase, 1998
Chase, M.W., Jr.,
NIST-JANAF Themochemical Tables, Fourth Edition,
J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951. [all data]
Lutz and Ryan, 1974
Lutz, B.L.; Ryan, J.A.,
Silicon carbide: its ground state and predicted spectrum,
Astrophys. J., 1974, 194, 753. [all data]
Lovas, 1974
Lovas, F.J.,
Small silicon molecules: possible sources of the unidentified molecular lines U81.5, U86.2, U89.2, and U90.7,
Astrophys. J., 1974, 193, 265. [all data]
Verhaegen, Stafford, et al., 1964
Verhaegen, G.; Stafford, F.E.; Drowart, J.,
Mass spectrometric study of the systems boron-carbon and boron-carbon-silicon,
J. Chem. Phys., 1964, 40, 1622. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Constants of diatomic molecules, References
- Symbols used in this document:
S°gas,1 bar Entropy of gas at standard conditions (1 bar) ΔfH°gas Enthalpy of formation of gas at standard conditions ΔfH°solid Enthalpy of formation of solid at standard conditions - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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