Isocyanic acid
- Formula: CHNO
- Molecular weight: 43.0247
- IUPAC Standard InChI: InChI=1S/CHNO/c2-1-3/h2H
- IUPAC Standard InChIKey: OWIKHYCFFJSOEH-UHFFFAOYSA-N
- CAS Registry Number: 75-13-8
- Chemical structure:
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Gas phase thermochemistry data
Go To: Top, References, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | -101.67 | kJ/mol | Review | Chase, 1998 | Data last reviewed in December, 1970 |
| ΔfH°gas | -97. ± 13. | kJ/mol | Ion | Okabe, 1970 | ALS |
| Quantity | Value | Units | Method | Reference | Comment |
| S°gas,1 bar | 238.22 | J/mol*K | Review | Chase, 1998 | Data last reviewed in December, 1970 |
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 1200. | 1200. to 6000. |
|---|---|---|
| A | 32.73428 | 71.59786 |
| B | 63.81479 | 5.912034 |
| C | -38.46142 | -1.122839 |
| D | 9.728052 | 0.074171 |
| E | -0.317587 | -9.813573 |
| F | -115.0136 | -144.3811 |
| G | 258.6482 | 296.4201 |
| H | -101.6712 | -101.6712 |
| Reference | Chase, 1998 | Chase, 1998 |
| Comment | Data last reviewed in December, 1970 | Data last reviewed in December, 1970 |
References
Go To: Top, Gas phase thermochemistry data, 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]
Okabe, 1970
Okabe, H.,
Photodissociation of HNCO in the vacuum ultraviolet; production of NCO A2Σ and NH (A3π, πC1),
J. Chem. Phys., 1970, 53, 3507-3515. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, 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 - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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