Oxygen

• Formula: O₂
• Molecular weight: 31.9988
• IUPAC Standard InChI: InChI=1S/O2/c1-2 Copy

  
• IUPAC Standard InChIKey: MYMOFIZGZYHOMD-UHFFFAOYSA-N Copy
• 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
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Phase change data
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Reaction thermochemistry data: reactions 1 to 50, reactions 51 to 70
  • Henry's Law data
  • Gas phase ion energetics data
  • Ion clustering data
  • Constants of diatomic molecules
  • Fluid Properties
• Data at other public NIST sites:
  • Microwave spectra (on physics lab web site)
  • Electron-Impact Ionization Cross Sections (on physics web site)
  • Gas Phase Kinetics Database
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Gas phase thermochemistry data

Go To: Top, Phase change data, 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.

Gas Phase Heat Capacity (Shomate Equation)

C_p° = 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
    C_p = heat capacity (cal/mol*K)
    H° = standard enthalpy (kcal/mol)
    S° = standard entropy (cal/mol*K)
    t = temperature (K) / 1000.

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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

Antoine Equation Parameters

log₁₀(P) = A − (B / (T + C))
    P = vapor pressure (atm)
    T = temperature (K)

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Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, 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.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Spectrum

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Additional Data

References

Go To: Top, Gas phase thermochemistry data, Phase change 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]

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, Mass spectrum (electron ionization), 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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