Oxalic acid

• Formula: C₂H₂O₄
• Molecular weight: 90.0349
• IUPAC Standard InChI: InChI=1S/C2H2O4/c3-1(4)2(5)6/h(H,3,4)(H,5,6) Copy

  
• IUPAC Standard InChIKey: MUBZPKHOEPUJKR-UHFFFAOYSA-N Copy
• CAS Registry Number: 144-62-7
• Chemical structure:
  This structure is also available as a 2d Mol file or as a computed 3d SD file
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• Other names: Ethanedioic acid; Aktisal; Aquisal; Oxiric acid; HOOCCOOH; Acide oxalique; Acido ossalico; Ethanedionic acid; Kyselina stavelova; NCI-C55209; Oxaalzuur; Oxalsaeure; Ethane-1,2-dioic acid; NSC 62774
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• Information on this page:
  • Gas phase thermochemistry data
  • Reaction thermochemistry data
  • Gas phase ion energetics data
  • Gas Chromatography
  • References
  • Notes
• Other data available:
  • Condensed phase thermochemistry data
  • Phase change data
  • Henry's Law data
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
  • X-ray Photoelectron Spectroscopy Database, version 5.0
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Gas phase thermochemistry 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 by: Glushko Thermocenter, Russian Academy of Sciences, Moscow

Constant pressure heat capacity of gas

Reaction thermochemistry 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:
B - John E. Bartmess
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.

Individual Reactions

C₂HO₄^- +  =

By formula: C₂HO₄^- + H⁺ = C₂H₂O₄

 + 2 =  + 2

By formula: C₄H₆O₄ + 2H₂O = C₂H₂O₄ + 2CH₄O

Gas phase ion energetics 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:
B - John E. Bartmess
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
LL - Sharon G. Lias and Joel F. Liebman

Ionization energy determinations

Appearance energy determinations

De-protonation reactions

C₂HO₄^- +  =

By formula: C₂HO₄^- + H⁺ = C₂H₂O₄

Gas Chromatography

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

Normal alkane RI, non-polar column, temperature ramp

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References

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Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Dorofeeva O.V., 1997
Dorofeeva O.V., Unpublished results. Thermocenter of Russian Academy of Science, Moscow, 1997. [all data]

Kumar, Prabhakar, et al., 2005
Kumar, M.R.; Prabhakar, S.; Nagaveni, V.; Vairamani, M., Estimation of gas-phase acidities of a series of dicarboxylic acids by the kinetic method, Rapid Commun. Mass Spectrom., 2005, 19, 8, 1053-1057, https://doi.org/10.1002/rcm.1888 . [all data]

Anthoney, Finch, et al., 1975
Anthoney, M.E.; Finch, A.; Stephens, M., The solution of dimethyl oxalate and oxalic acid in water and alkali. Standard enthalpy of formation of dimethyl oxalate, Thermochim. Acta, 1975, 12, 427-431. [all data]

McGlynn and Meeks, 1976
McGlynn, S.P.; Meeks, J.L., Photoelectron spectra of carbonyls, carbonates, oxalates and esterification effects, J. Electron Spectrosc. Relat. Phenom., 1976, 8, 85. [all data]

Meeks, Arnett, et al., 1975
Meeks, J.L.; Arnett, J.F.; Larson, D.B.; McGlynn, S.P., Photoelectron spectroscopy of carbonyls. Urea, oxamide, oxalic acid and oxamic acid, J. Am. Chem. Soc., 1975, 97, 3905. [all data]

Arnett, Newkome, et al., 1974
Arnett, J.F.; Newkome, G.; Mattice, W.L.; McGlynn, S.P., Excited electronic states of the α-dicarbonyls, J. Am. Chem. Soc., 1974, 96, 4385. [all data]

Chen and Holmes, 1994
Chen, H.; Holmes, J.L., The generation of OC₂O⁺ and OC₂O and a study of ionized OC₃O and C₂O by tandem mass spectrometry, Int. J. Mass Spectrom. Ion Processes, 1994, 133, 111. [all data]

Setkova, Risticevic, et al., 2007
Setkova, L.; Risticevic, S.; Pawliszyn, J., Rapid headspace solid-phase microextraction-gas chromatographic?time-of-flight mass spectrometric method for qualitative profiling of ice wine volatile fraction II: Classification of Canadian and Czech ice wines using statistical evaluation of the data, J. Chromatogr. A, 2007, 1147, 2, 224-240, https://doi.org/10.1016/j.chroma.2007.02.052 . [all data]

Notes

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• Symbols used in this document:
  

  AE	Appearance energy
  Cp,gas	Constant pressure heat capacity of gas
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions

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