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:
  • Phase change data
  • Reaction thermochemistry data
  • Henry's Law data
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Gas phase ion energetics data
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
  • X-ray Photoelectron Spectroscopy Database, version 5.0
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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
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
AC - William E. Acree, Jr., James S. Chickos
DH - Eugene S. Domalski and Elizabeth D. Hearing

Enthalpy of sublimation

Enthalpy of phase transition

Entropy of phase transition

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

Henry's Law 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: Rolf Sander

Henry's Law constant (water solution)

k_H(T) = k°_H exp(d(ln(k_H))/d(1/T) ((1/T) - 1/(298.15 K)))
k°_H = Henry's law constant for solubility in water at 298.15 K (mol/(kg*bar))
d(ln(k_H))/d(1/T) = Temperature dependence constant (K)

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.

Wilhoit and Shiao, 1964
Wilhoit, R.C.; Shiao, D., Thermochemistry of Biologically Important Compounds. Heats of Combustion of Solid Organic Acids, J. Chem. Eng. Data, 1964, 9, 595. [all data]

Bradley and Cleasby, 1953
Bradley, R.S.; Cleasby, T.G., The vapour pressure and lattice energy of hydrogen-bonded crystals. Part I. Oxamide, oxamic acid, and rubeanie acid, J. Chem. Soc., 1953, 1681-16. [all data]

Granovskaya, 1947
Granovskaya, A., Russ. J. Phys. Chem., 1947, 21, 967. [all data]

Noyes and Wobbe, 1926
Noyes, W. Albert; Wobbe, Delbert E., THE VAPOR PRESSURE OF ANHYDROUS OXALIC ACID, J. Am. Chem. Soc., 1926, 48, 7, 1882-1887, https://doi.org/10.1021/ja01418a012 . [all data]

Petropavlov, Tsygankova, et al., 1988
Petropavlov, N.N.; Tsygankova, I.G.; Teslenko, L.A., Microcalorimetric investigation of polymorphic transitions in organic crystals, Sov. Phys. Crystallogr., 1988, 33(6), 853-855. [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]

Notes

Go To: Top, Phase change data, Reaction thermochemistry data, Henry's Law data, References

• Symbols used in this document:
  

  Tfus	Fusion (melting) point
  d(ln(kH))/d(1/T)	Temperature dependence parameter for Henry's Law constant
  k°H	Henry's Law constant at 298.15K
  ΔHtrs	Enthalpy of phase transition
  ΔStrs	Entropy of phase transition
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔsubH	Enthalpy of sublimation
  ΔsubH°	Enthalpy of sublimation at standard conditions

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