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:
- Gas phase thermochemistry 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 (electron ionization)
- Constants of diatomic molecules
- Fluid Properties
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Phase change data
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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:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| Ttriple | 0. | K | N/A | Roder, Childs, et al., 1973 | TRC |
| Ttriple | 13.95 | K | N/A | Clusius and Weigand, 1940 | Uncertainty assigned by TRC = 0.06 K; see property X for dP/dT for c-l equil.; TRC |
| Ttriple | 13.96 | K | N/A | Henning and Otto, 1936 | Uncertainty assigned by TRC = 0.05 K; temperature measured with He gas thermometer; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| Ptriple | 0. | bar | N/A | Roder, Childs, et al., 1973 | TRC |
| Ptriple | 0.0721 | bar | N/A | Henning and Otto, 1936 | Uncertainty assigned by TRC = 0.0004 bar; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| Tc | 33.18 | K | N/A | Onnes, Crommelin, et al., 1917 | Uncertainty assigned by TRC = 0.2 K; derived from P-V-T measurements; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| Pc | 13.00 | bar | N/A | Onnes, Crommelin, et al., 1917 | Uncertainty assigned by TRC = 0.0119 bar; derived from vapor pressure extrapolated to Tc; TRC |
| Quantity | Value | Units | Method | Reference | Comment |
| ρc | 15.4 | mol/l | N/A | Onnes, Crommelin, et al., 1917 | Uncertainty assigned by TRC = 2. mol/l; by extrapolation of rectilinear diameter to Tc; TRC |
Antoine Equation Parameters
log10(P) = A − (B / (T + C))
P = vapor pressure (bar)
T = temperature (K)
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| Temperature (K) | A | B | C | Reference | Comment |
|---|---|---|---|---|---|
| 21.01 to 32.27 | 3.54314 | 99.395 | 7.726 | van Itterbeek, Verbeke, et al., 1964 | Coefficents calculated by NIST from author's data. |
References
Go To: Top, Phase change data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
Roder, Childs, et al., 1973
Roder, H.M.; Childs, G.E.; McCarty, R.D.; Angerhofer, P.E.,
Survey of the Prop. of the Hydrogen Isotopes Below Their Critical Temp, Natl. Bur. Stand. (U. S.), 1973. [all data]
Clusius and Weigand, 1940
Clusius, K.; Weigand, K.,
Melting Curves of the Gases A, Kr, Xe, CH4, CH3D, CD4, C2H4, C2H6, COS, and PH3 to 200 Atmospheres Pressure. The Chane of Volume on Melting,
Z. Phys. Chem., Abt. B, 1940, 46, 1-37. [all data]
Henning and Otto, 1936
Henning, F.; Otto, J.,
Vapor pressure curves and triple points in the temperature region from 14 to 90 k,
Phys. Z., 1936, 37, 633-8. [all data]
Onnes, Crommelin, et al., 1917
Onnes, H.K.; Crommelin, C.-A.; Cath, P.G.,
Isothermals of di-atomic substances and their binary mixtures. XIX. A preliminary determination of the critical point of hydrogen.,
Proc. K. Ned. Akad. Wet., 1917, 20, 178-184. [all data]
van Itterbeek, Verbeke, et al., 1964
van Itterbeek, A.; Verbeke, O.; Theewes, F.; Staes, K.; de Boelpaep, J.,
The Difference in Vapour Pressure Between Normal and Equilibrium Hydrogen. Vapour Pressure of Normal Hydrogen Between 20 ºK and 32 ºK,
Physica (Amsterdam), 1964, 30, 6, 1238-1244, https://doi.org/10.1016/0031-8914(64)90114-4
. [all data]
Notes
Go To: Top, Phase change data, References
- Symbols used in this document:
Pc Critical pressure Ptriple Triple point pressure Tc Critical temperature Ttriple Triple point temperature ρc Critical density - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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