Hydrogen
- Formula: H2
- Molecular weight: 2.01588
- IUPAC Standard InChI: InChI=1S/H2/h1H
- IUPAC Standard InChIKey: UFHFLCQGNIYNRP-UHFFFAOYSA-N
- CAS Registry Number: 1333-74-0
- Chemical structure:
This structure is also available as a 2d Mol file or as a computed 3d SD file
The 3d structure may be viewed using Java or Javascript. - Isotopologues:
- Other names: Dihydrogen; o-Hydrogen; p-Hydrogen; Molecular hydrogen; H2; UN 1049; UN 1966
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- 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
- Constants of diatomic molecules
- Fluid Properties
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Gas phase thermochemistry data
Go To: Top, Mass spectrum (electron ionization), 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 |
|---|---|---|---|---|---|
| S°gas,1 bar | 31.2333 ± 0.0007 | cal/mol*K | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
| S°gas,1 bar | 31.233 | cal/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 (cal/mol*K)
H° = standard enthalpy (kcal/mol)
S° = standard entropy (cal/mol*K)
t = temperature (K) / 1000.
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| Temperature (K) | 298. to 1000. | 1000. to 2500. | 2500. to 6000. |
|---|---|---|---|
| A | 7.903006 | 4.436683 | 10.376090 |
| B | -2.715922 | 2.929578 | -1.026071 |
| C | 2.732508 | -0.683505 | 0.304117 |
| D | -0.662733 | 0.064110 | -0.023154 |
| E | -0.037896 | 0.472751 | -4.907711 |
| F | -2.385468 | -0.274244 | -9.205344 |
| G | 41.278196 | 37.353760 | 38.738373 |
| 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 |
Mass spectrum (electron ionization)
Go To: Top, Gas 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: NIST Mass Spectrometry Data Center, William E. Wallace, director
Spectrum
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Additional Data
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Due to licensing restrictions, this spectrum cannot be downloaded.
| Owner | NIST Mass Spectrometry Data Center Collection (C) 2014 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved. |
|---|---|
| Origin | American Petroleum Institute Research Project 44 |
| NIST MS number | 245692 |
References
Go To: Top, Gas phase thermochemistry data, Mass spectrum (electron ionization), 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]
Notes
Go To: Top, Gas phase thermochemistry data, Mass spectrum (electron ionization), References
- Symbols used in this document:
S°gas,1 bar Entropy of gas at standard conditions (1 bar) - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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