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
  • Reaction thermochemistry data (reactions 1 to 50)
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Reaction thermochemistry data: 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
• Options:
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Gas phase thermochemistry data

Go To: Top, Phase change data, Reaction thermochemistry 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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Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, 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.

Data compiled as indicated in comments:
B - John E. Bartmess
M - Michael M. Meot-Ner (Mautner) and Sharon G. Lias
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Reactions 1 to 50

 +  = ( • )

By formula: O₂^- + O₂ = (O₂^- • O₂)

Free energy of reaction

 +  = ( • )

By formula: O₂⁺ + O₂ = (O₂⁺ • O₂)

Free energy of reaction

(HO₂⁺ • 2) +  = (HO₂⁺ • 3)

By formula: (HO₂⁺ • 2O₂) + O₂ = (HO₂⁺ • 3O₂)

Free energy of reaction

( • 7 • ) +  = ( • 8 • )

By formula: (O₂^- • 7N₂ • O₂) + N₂ = (O₂^- • 8N₂ • O₂)

O^- +  = (O^- • )

By formula: O^- + O₂ = (O^- • O₂)

( • ) +  = ( • 2)

By formula: (O₂⁺ • O₂) + O₂ = (O₂⁺ • 2O₂)

(HO₂⁺ • ) +  = (HO₂⁺ • 2)

By formula: (HO₂⁺ • O₂) + O₂ = (HO₂⁺ • 2O₂)

( • 3) +  = ( • 4)

By formula: (O₂⁺ • 3O₂) + O₂ = (O₂⁺ • 4O₂)

( • 2) +  = ( • 3)

By formula: (O₂⁺ • 2O₂) + O₂ = (O₂⁺ • 3O₂)

( • 4) +  = ( • 5)

By formula: (O₂⁺ • 4O₂) + O₂ = (O₂⁺ • 5O₂)

O₃^- +  = (O₃^- • )

By formula: O₃^- + O₂ = (O₃^- • O₂)

 +  = ( • )

By formula: NO^- + O₂ = (NO^- • O₂)

Free energy of reaction

( • 6) +  = ( • 7)

By formula: (O₂^- • 6O₂) + O₂ = (O₂^- • 7O₂)

( • 7) +  = ( • 8)

By formula: (O₂⁺ • 7O₂) + O₂ = (O₂⁺ • 8O₂)

( • ) +  = ( •  • )

By formula: (O₂⁺ • O₂) + N₂ = (O₂⁺ • N₂ • O₂)

(H₃⁺ • ) +  = (H₃⁺ • 2)

By formula: (H₃⁺ • O₂) + O₂ = (H₃⁺ • 2O₂)

(O₃^- • 4) +  = (O₃^- • 5)

By formula: (O₃^- • 4O₂) + O₂ = (O₃^- • 5O₂)

H₃⁺ +  = (H₃⁺ • )

By formula: H₃⁺ + O₂ = (H₃⁺ • O₂)

(O₂S^- • 2 • ) +  = (O₂S^- • 3 • )

By formula: (O₂S^- • 2O₂S • O₂) + O₂S = (O₂S^- • 3O₂S • O₂)

(O₂S^- •  • ) +  = (O₂S^- • 2 • )

By formula: (O₂S^- • O₂S • O₂) + O₂S = (O₂S^- • 2O₂S • O₂)

(O₃S^- •  • ) +  = (O₃S^- • 2 • )

By formula: (O₃S^- • O₂S • O₂) + O₂S = (O₃S^- • 2O₂S • O₂)

 +  = ( • )

By formula: O⁺ + O₂ = (O⁺ • O₂)

(O₃S^- • ) +  = (O₃S^- •  • )

By formula: (O₃S^- • O₂) + O₂S = (O₃S^- • O₂S • O₂)

(O₂S^- • ) +  = (O₂S^- •  • )

By formula: (O₂S^- • O₂) + O₂S = (O₂S^- • O₂S • O₂)

( • 2 • ) +  = ( • 3 • )

By formula: (O₂^- • 2N₂ • O₂) + N₂ = (O₂^- • 3N₂ • O₂)

( • 3 • ) +  = ( • 4 • )

By formula: (O₂^- • 3N₂ • O₂) + N₂ = (O₂^- • 4N₂ • O₂)

( • 4 • ) +  = ( • 5 • )

By formula: (O₂^- • 4N₂ • O₂) + N₂ = (O₂^- • 5N₂ • O₂)

( • 5 • ) +  = ( • 6 • )

By formula: (O₂^- • 5N₂ • O₂) + N₂ = (O₂^- • 6N₂ • O₂)

( • 6 • ) +  = ( • 7 • )

By formula: (O₂^- • 6N₂ • O₂) + N₂ = (O₂^- • 7N₂ • O₂)

( •  • ) +  = ( • 2 • )

By formula: (O₂^- • N₂ • O₂) + N₂ = (O₂^- • 2N₂ • O₂)

( • 2) +  = ( • 3)

By formula: (NO^- • 2O₂) + O₂ = (NO^- • 3O₂)

( • 3) +  = ( • 4)

By formula: (NO^- • 3O₂) + O₂ = (NO^- • 4O₂)

( • 4) +  = ( • 5)

By formula: (NO^- • 4O₂) + O₂ = (NO^- • 5O₂)

( • ) +  = ( • 2)

By formula: (NO^- • O₂) + O₂ = (NO^- • 2O₂)

(HO₂⁺ • 3) +  = (HO₂⁺ • 4)

By formula: (HO₂⁺ • 3O₂) + O₂ = (HO₂⁺ • 4O₂)

(HO₂⁺ • 4) +  = (HO₂⁺ • 5)

By formula: (HO₂⁺ • 4O₂) + O₂ = (HO₂⁺ • 5O₂)

(HO₂⁺ • 5) +  = (HO₂⁺ • 6)

By formula: (HO₂⁺ • 5O₂) + O₂ = (HO₂⁺ • 6O₂)

(HO₂⁺ • 6) +  = (HO₂⁺ • 7)

By formula: (HO₂⁺ • 6O₂) + O₂ = (HO₂⁺ • 7O₂)

(HO₂⁺ • 7) +  = (HO₂⁺ • 8)

By formula: (HO₂⁺ • 7O₂) + O₂ = (HO₂⁺ • 8O₂)

(HO₂⁺ • 8) +  = (HO₂⁺ • 9)

By formula: (HO₂⁺ • 8O₂) + O₂ = (HO₂⁺ • 9O₂)

(HO₂⁺ • ) +  = (HO₂⁺ •  • )

By formula: (HO₂⁺ • O₂) + H₂ = (HO₂⁺ • H₂ • O₂)

( • ) +  = ( •  • )

By formula: (O₂^- • O₂) + N₂ = (O₂^- • N₂ • O₂)

2 +  = 2

By formula: 2C₂H₆S + O₂ = 2C₂H₆OS

=  + 0.5

By formula: C₂H₆O₂S = C₂H₆OS + 0.5O₂

( • 2) +  = ( • 3)

By formula: (O₂^- • 2O₂) + O₂ = (O₂^- • 3O₂)

( • 3) +  = ( • 4)

By formula: (O₂^- • 3O₂) + O₂ = (O₂^- • 4O₂)

( • 4) +  = ( • 5)

By formula: (O₂^- • 4O₂) + O₂ = (O₂^- • 5O₂)

( • 5) +  = ( • 6)

By formula: (O₂^- • 5O₂) + O₂ = (O₂^- • 6O₂)

( • 5) +  = ( • 6)

By formula: (O₂⁺ • 5O₂) + O₂ = (O₂⁺ • 6O₂)

( • 6) +  = ( • 7)

By formula: (O₂⁺ • 6O₂) + O₂ = (O₂⁺ • 7O₂)

Mass spectrum (electron ionization)

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

References

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

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]

Hiraoka, 1988
Hiraoka, K., A Determination of the Stabilities of O2+(O2)n and O2-(O2)n with n = 1 - 8 from Measurements of the Gas-Phase Ion Equilibria, J. Chem. Phys., 1988, 89, 5, 3190, https://doi.org/10.1063/1.454976 . [all data]

Conway and Nesbit, 1968
Conway, D.C.; Nesbit, L.E., Stability of O₄^-, J. Chem. Phys., 1968, 48, 1, 509, https://doi.org/10.1063/1.1667956 . [all data]

Hiraoka, 1888
Hiraoka, K., A Determination of the Stability of O₂⁺(O₂)n and O₂^-(O₂)n with n=1-8 from Measurements of the Gas Phase Ion Equilibria, J. Chem. Phys., 1888, 89, 5, 3190, https://doi.org/10.1063/1.454976 . [all data]

Sherwood, Hanold, et al., 1996
Sherwood, C.R.; Hanold, K.A.; Garner, M.C.; Strong, K.M.; Continetti, R.E., Translational Spectroscopy Studies of the Photodissociation Dynamics of O4-, J. Chem. Phys., 1996, 105, 24, 10803, https://doi.org/10.1063/1.472888 . [all data]

Aquino, Taylor, et al., 2001
Aquino, A.J.A.; Taylor, P.R.; Walch, S.P., Structure, properties, and photodissociation of O-4(-), J. Chem. Phys., 2001, 114, 7, 3010-3017, https://doi.org/10.1063/1.1288379 . [all data]

Payzant J.D. and Kebarle, 1972
Payzant J.D.; Kebarle, P., Kinetics and Reactions Leading to O2-(H2O)n in Moist Oxygen, J. Chem. Phys., 1972, 56, 7, 3482, https://doi.org/10.1063/1.1677723 . [all data]

Pack and Phelps, 1971
Pack, J.L.; Phelps, A.V., Hydration of Oxygen Negative Ions, Bull. Am. Phys. Soc., 1971, 16, 214. [all data]

Parkes, 1971
Parkes, D.A., Electron Attachment and Negative Ion-Molecule Reactions in Pure O₂, Trans. Farad. Soc., 1971, 97, 711, https://doi.org/10.1039/tf9716700711 . [all data]

Conway and Janik, 1970
Conway, D.C.; Janik, G.S., Determination of the Bond Energies for the Series O2 - O2+ through O2 - O10+, J. Chem. Phys., 1970, 53, 5, 1859, https://doi.org/10.1063/1.1674262 . [all data]

Durden, Kebarle, et al., 1969
Durden, D.A.; Kebarle, P.; Good, A., Thermal Ion-Molecule Reaction Rate Constants at Pressures up to 10 torr with a Pulsed Mass Spectrometer. Reactions in Methane, Krypton, and Oxygen, J. Chem. Phys., 1969, 50, 2, 805, https://doi.org/10.1063/1.1671133 . [all data]

Yang and Conway, 1964
Yang, J.H.; Conway, D.C., Bonding in Ion Clusters. I. O4+, J. Chem. Phys., 1964, 40, 6, 1729, https://doi.org/10.1063/1.1725389 . [all data]

Rakshit and Warneck, 1981
Rakshit, A.B.; Warneck, P., Formation and Reactions of O2+.CO2, O2+.H2O and O2+(CO2)2 Ions, Int. J. Mass Spectrom Ion Phys., 1981, 40, 2, 135, https://doi.org/10.1016/0020-7381(81)80037-X . [all data]

Rakshit and Warneck, 1980
Rakshit, A.B.; Warneck, P., A Drift Chamber Study of the Formation of Water Cluster Ions in Oxygen, J. Chem. Phys., 1980, 73, 10, 5074, https://doi.org/10.1063/1.439985 . [all data]

Howard, Bierbaum, et al., 1972
Howard, C.J.; Bierbaum, V.M.; Rundle, H.W.; Kaufman, F., Kinetics and Mechanism of Formation of Water Cluster Ions from O2+ and H2O+, J. Chem. Phys., 1972, 57, 8, 3491, https://doi.org/10.1063/1.1678783 . [all data]

Adams and Bohme, 1970
Adams, N.G.; Bohme, D., Flowing Afterglow Studies of Formation and Reactions of Cluster Ions of O₂⁺, O₂^-, and O^-, J. Chem. Phys., 1970, 52, 6, 3133, https://doi.org/10.1063/1.1673449 . [all data]

Hiraoka and Mori, 1989
Hiraoka, K.; Mori, T., Gas Phase Stabilities of the Cluster Ions H+(CO)2(CO)n, H+(N2)2(N2)n and H+(O2)2(O2)n with n = 1 - 14, Chem. Phys., 1989, 137, 1-3, 345, https://doi.org/10.1016/0301-0104(89)87119-8 . [all data]

Hiraoka, Saluja, et al., 1979
Hiraoka, K.; Saluja, P.P.S.; Kebarle, P., Stabilities of Complexes (N2)nH+, (CO)nH+ and (O2)nH+ for n = 1 to 7 Based on Gas Phase Ion Equilibrium Measurements, Can. J. Chem., 1979, 57, 16, 2159, https://doi.org/10.1139/v79-346 . [all data]

Hiraoka, 1988, 2
Hiraoka, K., Determination of the Stabilities of O₃^-(N₂)n, O₃^-(O₂)n, and O₄^-(N₂)n from Measurements of the Gas Phase Equilibria, Chem. Phys., 1988, 125, 2-3, 439, https://doi.org/10.1016/0301-0104(88)87096-4 . [all data]

Hiller and Vestal, 1981
Hiller, J.F.; Vestal, M.L., Laser Photodissociation of O3- by Triple Quadrupole Mass Spectrometry, J. Chem. Phys., 1981, 74, 11, 6096, https://doi.org/10.1063/1.441053 . [all data]

Novich, Engelking, et al., 1979
Novich, S.E.; Engelking, P.C.; Jones, P.L.; Futrell, J.H.; Lineberger, W.C., Laser photoelectron, photodetachment, and photodestruction spectra of O₃-, J. Chem. Phys., 1979, 70, 2652. [all data]

Cosby, Moseley, et al., 1978
Cosby, P.C.; Moseley, J.T.; Peterson, J.R.; Ling, J.H., Photodissociation spectroscopy of O₃, J. Chem. Phys., 1978, 69, 2771. [all data]

Lifschitz, Wu, et al., 1978
Lifschitz, C.; Wu, R.L.C.; Tiernan, T.O.; Terwillinger, D.T., Negative Ion - Molecule Reactions of Ozone and Their Implications on the Thermochemistry of O3-, J. Chem. Phys., 1978, 68, 1, 247, https://doi.org/10.1063/1.435489 . [all data]

Hiraoka and Yamabe, 1991
Hiraoka, K.; Yamabe, S., Cluster Ions: Gas Phase Stabilities of NO+(O2)n and NO+(CO2)n with n = 1 - 5, J. Chem. Phys., 1991, 95, 9, 6800, https://doi.org/10.1063/1.461518 . [all data]

Dunkin, Fehsenfeld, et al., 1971
Dunkin, D.B.; Fehsenfeld, F.C.; Schelmetekopf, A.L.; Ferguson, E.E., Three-Body Association Reactions of NO+ with O2, N2, and CO2, J. Chem. Phys., 1971, 54, 9, 3817, https://doi.org/10.1063/1.1675432 . [all data]

Speller and Fitaire, 1983
Speller, C.V.; Fitaire, M., Proceedings of the 16th International Conference on Phenomena of Ionized Gases, H. Boetticher, H. Wenk and E. Shulz - Gulde, ed(s)., ICPIG, Dusseldorf, 1983, 568. [all data]

Vacher, Jorda, et al., 1992
Vacher, J.R.; Jorda, M.; Leduc, E.; Fitaire, M., A Determination of the Stabilities of Negative Ion Clusters in SO2 and SO2-O2 Mixtures, Int. J. Mass Spectrom. Ion Proc., 1992, 114, 3, 149, https://doi.org/10.1016/0168-1176(92)80033-W . [all data]

Hiller and Vestal, 1982
Hiller, J.F.; Vestal, M.L., Laser Photodissociation of O3+ and the Energetics of Ozone and its Ions, J. Chem. Phys., 1982, 77, 3, 1248, https://doi.org/10.1063/1.444000 . [all data]

Linn, Ono, et al., 1981
Linn, S.H.; Ono, Y.; Ng, C.Y., A Study of the Ion - Molecule Half Reactions O2+(a4piu, v)...(O2)m ---> O2m+1 + O, m=1, 2, 3, Using the Molecular Beam Photoionization Method, J. Chem. Phys., 1981, 74, 6, 3348, https://doi.org/10.1063/1.441487 . [all data]

Mosely, Ozenne, et al., 1981
Mosely, J.T.; Ozenne, J.B.; Cosby, P.C., Photofragment Spectroscopy of O3+, J. Chem. Phys., 1981, 74, 1, 337, https://doi.org/10.1063/1.440839 . [all data]

Douglas, 1946
Douglas, T.B., Heats of formation of liquid methyl sulfoxide and crystalline methyl sulfone at 18°, J. Am. Chem. Soc., 1946, 68, 1072-1076. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Notes

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry 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)
  T	Temperature
  Tboil	Boiling point
  Tc	Critical temperature
  Tfus	Fusion (melting) point
  Ttriple	Triple point temperature
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔrS°	Entropy of reaction at standard conditions
  ρc	Critical density

• Data from NIST Standard Reference Database 69: NIST Chemistry WebBook
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