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)
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Reaction thermochemistry data: reactions 51 to 70
  • Henry's Law data
  • Ion clustering data
  • Mass spectrum (electron ionization)
  • 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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• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

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Gas phase thermochemistry data

Go To: Top, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, 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 (J/mol*K)
    H° = standard enthalpy (kJ/mol)
    S° = standard entropy (J/mol*K)
    t = temperature (K) / 1000.

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View table.

Phase change data

Go To: Top, Gas phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics 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

Antoine Equation Parameters

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

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Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Phase change data, Gas phase ion energetics 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:
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)

Gas phase ion energetics data

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 evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
B - John E. Bartmess
MM - Michael M. Meot-Ner (Mautner)
LL - Sharon G. Lias and Joel F. Liebman
LBLHLM - Sharon G. Lias, John E. Bartmess, Joel F. Liebman, John L. Holmes, Rhoda D. Levin, and W. Gary Mallard
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

View reactions leading to O₂⁺ (ion structure unspecified)

Electron affinity determinations

Proton affinity at 298K

Ionization energy determinations

Appearance energy determinations

Anion protonation reactions

 +  =

By formula: O₂^- + H⁺ = HO₂

References

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics 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
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Streng, A.G., Miscibility and Compatibility of Some Liquid and Solidified Gases at Low Temperature, J. Chem. Eng. Data, 1971, 16, 357. [all data]

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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]

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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]

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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]

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Payzant J.D. and Kebarle, 1972
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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]

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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]

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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]

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Notes

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• Symbols used in this document:
  

  AE	Appearance energy
  EA	Electron affinity
  IE (evaluated)	Recommended ionization energy
  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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