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Hydrogen
- Formula: H2
- Molecular weight: 2.02
- IUPAC International Chemical Identifer:
- InChI=1/H2/h1H
- Download the identifier in a file.
- CAS Registry Number: 1333-74-0
- Chemical structure:
This structure is also available as a 2d Mol file . - Isotopomers:
- Other names: Dihydrogen; o-Hydrogen; p-Hydrogen; Molecular hydrogen; H2; UN 1049; UN 1966
- Information on this page:
- Other data available:
- Phase change data
- Reaction thermochemistry data: reactions 1 to 50, reactions 51 to 100, reactions 101 to 150, reactions 151 to 200, reactions 201 to 250, reactions 251 to 300, reactions 301 to 350, reactions 351 to 400, reactions 401 to 450, reactions 451 to 500, reactions 501 to 550, reactions 551 to 600, reactions 601 to 621
- Henry's Law data
- Gas phase ion energetics data
- Ion clustering data
- Mass Spectrum
- Constants of Diatomic Molecules
- Fluid Properties
- Data at other NIST sites:
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Gas phase thermochemistry data
Go To: Top, References, Notes / Error Report
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 |
|---|---|---|---|---|---|
| S°gas,1 bar | 130.680 ± 0.003 | J/mol*K | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
| S°gas,1 bar | 130.68 | J/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1977 |
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.
View plot Requires a Java capable browser.
| Temperature (K) | 298. - 1000. | 1000. - 2500. | 2500. - 6000. |
|---|---|---|---|
| A | 33.066178 | 18.563083 | 43.413560 |
| B | -11.363417 | 12.257357 | -4.293079 |
| C | 11.432816 | -2.859786 | 1.272428 |
| D | -2.772874 | 0.268238 | -0.096876 |
| E | -0.158558 | 1.977990 | -20.533862 |
| F | -9.980797 | -1.147438 | -38.515158 |
| G | 172.707974 | 156.288133 | 162.081354 |
| H | 0.0 | 0.0 | 0.0 |
| Reference | Chase, 1998 | Chase, 1998 | Chase, 1998 |
| Comment | Data last reviewed in March, 1977; New parameter fit October 2001 | Data last reviewed in March, 1977; New parameter fit October 2001 | Data last reviewed in March, 1977; New parameter fit October 2001 |
References
Go To: Top, Gas phase thermochemistry data, Notes / Error Report
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]
Notes / Error Report
Go To: Top, Gas phase thermochemistry data, References
- Data from NIST Standard Reference Database 69, June 2005 Release: NIST Chemistry WebBook
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