Hydrogen atom
- Formula: H
- Molecular weight: 1.00794
- IUPAC Standard InChI: InChI=1S/H
- IUPAC Standard InChIKey: YZCKVEUIGOORGS-UHFFFAOYSA-N
- CAS Registry Number: 12385-13-6
- Chemical structure:
This structure is also available as a 2d Mol file - Isotopologues:
- Permanent link for this species. Use this link for bookmarking this species for future reference.
- Information on this page:
- Other data available:
- Data at other public NIST sites:
- NIST Atomic Spectra Database - Lines Holdings (on physics web site)
- NIST Atomic Spectra Database - Levels Holdings (on physics web site)
- NIST Atomic Spectra Database - Ground states and ionization energies (on physics web site)
- Electron-Impact Ionization Cross Sections (on physics web site)
- Gas Phase Kinetics Database
- Options:
Data at NIST subscription sites:
NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.
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.
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔfH°gas | 52.103 ± 0.001 | kcal/mol | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
| ΔfH°gas | 52.103 | kcal/mol | Review | Chase, 1998 | Data last reviewed in March, 1982 |
| Quantity | Value | Units | Method | Reference | Comment |
| S°gas,1 bar | 27.4180 ± 0.0005 | cal/mol*K | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
| S°gas,1 bar | 27.419 | cal/mol*K | Review | Chase, 1998 | Data last reviewed in March, 1982 |
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.
View plot Requires a JavaScript / HTML 5 canvas capable browser.
| Temperature (K) | 298. to 6000. |
|---|---|
| A | 4.967981 |
| B | 1.159331×10-10 |
| C | -3.783261×10-11 |
| D | 3.645079×10-12 |
| E | 7.639451×10-12 |
| F | 50.62189 |
| G | 33.43000 |
| H | 52.10311 |
| Reference | Chase, 1998 |
| Comment | Data last reviewed in March, 1982 |
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.
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, 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
- The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
- Customer support for NIST Standard Reference Data products.