Oxygen
- Formula: O2
- Molecular weight: 31.9988
- IUPAC Standard InChIKey: MYMOFIZGZYHOMD-UHFFFAOYSA-N
- CAS Registry Number: 7782-44-7
- 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. - Other names: Molecular oxygen; Oxygen molecule; Pure oxygen; O2; Liquid oxygen; UN 1072; UN 1073; Dioxygen
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Gas phase thermochemistry data
Go To: Top, Phase change data, 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 | 49.033 ± 0.001 | cal/mol*K | Review | Cox, Wagman, et al., 1984 | CODATA Review value |
S°gas,1 bar | 49.032 | 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) | 100. to 700. | 700. to 2000. | 2000. to 6000. |
---|---|---|---|
A | 7.486219 | 7.177904 | 4.997876 |
B | -4.836356 | 2.096791 | 2.562312 |
C | 13.83041 | -0.953187 | -0.482910 |
D | -8.725201 | 0.188411 | 0.035002 |
E | -0.001762 | -0.177246 | 2.209781 |
F | -2.127981 | -2.706664 | 1.275730 |
G | 58.98530 | 56.44510 | 56.79219 |
H | 0.0 | 0.0 | 0.0 |
Reference | Chase, 1998 | Chase, 1998 | Chase, 1998 |
Comment | Data last reviewed in March, 1977; New parameter fit January 2009 | Data last reviewed in March, 1977; New parameter fit January 2009 | Data last reviewed in March, 1977; New parameter fit January 2009 |
Phase change data
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 as indicated in comments:
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
Quantity | Value | Units | Method | Reference | Comment |
---|---|---|---|---|---|
Tboil | 90.2 | K | N/A | Streng, 1971 | Uncertainty assigned by TRC = 0.2 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Tfus | 54.8 | K | N/A | Streng, 1971 | Uncertainty assigned by TRC = 0.2 K; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Ttriple | 54.33 | K | N/A | Henning and Otto, 1936 | Uncertainty assigned by TRC = 0.06 K; temperature measured with He gas thermometer; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Tc | 154.58 | K | N/A | Pentermann and Wagner, 1978 | Uncertainty assigned by TRC = 0.0015 K; TRC |
Tc | 154.58 | K | N/A | Wagner, Ewers, et al., 1976 | Uncertainty assigned by TRC = 0.0015 K; TRC |
Tc | 155.15 | K | N/A | Cardoso, 1915 | Uncertainty assigned by TRC = 0.3 K; 4 determinations with same result; TRC |
Quantity | Value | Units | Method | Reference | Comment |
Pc | 49.77 | atm | N/A | Wagner, Ewers, et al., 1976 | Uncertainty assigned by TRC = 0.005 atm; Vapour-pressure measurements give pc=5.04332 MPa at Tc from L.A.Weber, 1970 PRT, IPTS-68, PP+ differential pressure transducer.; TRC |
Pc | 49.3800 | atm | N/A | Cardoso, 1915 | Uncertainty assigned by TRC = 0.2999 atm; TRC |
Pc | 49.2700 | atm | N/A | Cardoso, 1915 | Uncertainty assigned by TRC = 0.2999 atm; TRC |
Pc | 49.2000 | atm | N/A | Cardoso, 1915 | Uncertainty assigned by TRC = 0.2999 atm; TRC |
Quantity | Value | Units | Method | Reference | Comment |
ρc | 13.60 | mol/l | N/A | Pentermann and Wagner, 1978 | Uncertainty assigned by TRC = 0.014 mol/l; from density measurements 65 to 300 K, Tc from Weber, 1970; TRC |
Antoine Equation Parameters
log10(P) = A − (B / (T + C))
P = vapor pressure (atm)
T = temperature (K)
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Temperature (K) | A | B | C | Reference | Comment |
---|---|---|---|---|---|
54.36 to 100.16 | 3.85274 | 325.675 | -5.667 | Brower and Thodos, 1968 | Coefficents calculated by NIST from author's data. |
54.36 to 154.33 | 3.9466 | 340.024 | -4.144 | Brower and Thodos, 1968 | Coefficents calculated by NIST from author's data. |
References
Go To: Top, Gas phase thermochemistry data, Phase change 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]
Streng, 1971
Streng, A.G.,
Miscibility and Compatibility of Some Liquid and Solidified Gases at Low Temperature,
J. Chem. Eng. Data, 1971, 16, 357. [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]
Pentermann and Wagner, 1978
Pentermann, W.; Wagner, W.,
New pressure-density-temperature measurements and new rational equations for the saturated liquid and vapor densities of oxygen,
J. Chem. Thermodyn., 1978, 10, 1161-1172. [all data]
Wagner, Ewers, et al., 1976
Wagner, W.; Ewers, J.; Pentermann, W.,
A New Vapor-Pressure Measurement and a New Rational Vapor-Pressure Equation for Oxygen,
J. Chem. Thermodyn., 1976, 8, 1049. [all data]
Cardoso, 1915
Cardoso, E.,
Study of the Critical Point of Several Difficultly LIquifiable Gases: Nitrogen, Carbon Monoxide, Oxygen and Methane,
J. Chim. Phys. Phys.-Chim. Biol., 1915, 13, 312. [all data]
Brower and Thodos, 1968
Brower, G.T.; Thodos, G.,
Vapor Pressures of Liquid Oxygen Between the Triple Point and Critical Point,
J. Chem. Eng. Data, 1968, 13, 2, 262-264, https://doi.org/10.1021/je60037a038
. [all data]
Notes
Go To: Top, Gas phase thermochemistry data, Phase change data, References
- Symbols used in this document:
Pc Critical pressure S°gas,1 bar Entropy of gas at standard conditions (1 bar) Tboil Boiling point Tc Critical temperature Tfus Fusion (melting) point Ttriple Triple point temperature ρc Critical density - Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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