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
  The 3d structure may be viewed using Java or Javascript.
• 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
• Permanent link for this species. Use this link for bookmarking this species for future reference.
• Information on this page:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Reaction thermochemistry data
  • Mass spectrum (electron ionization)
  • References
  • Notes
• Other data available:
  • Henry's Law data
  • Gas phase ion energetics data
  • UV/Visible spectrum
  • Gas Chromatography
• Data at other public NIST sites:
  • Gas Phase Kinetics Database
  • X-ray Photoelectron Spectroscopy Database, version 5.0
• Options:
  • Switch to calorie-based units

Data at NIST subscription sites:

• NIST / TRC Web Thermo Tables, professional edition (thermophysical and thermochemical data)

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.

Gas phase thermochemistry data

Go To: Top, Condensed phase thermochemistry data, 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.

Data compiled by: Glushko Thermocenter, Russian Academy of Sciences, Moscow

Constant pressure heat capacity of gas

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, 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.

Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Constant pressure heat capacity of solid

Phase change data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry 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.

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

Go To: Top, Gas phase thermochemistry data, Condensed 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
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

Mass spectrum (electron ionization)

Go To: Top, Gas phase thermochemistry data, Condensed 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

Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.

For Zoom

1.) Enter the desired X axis range (e.g., 100, 200)

2.) Check here for automatic Y scaling

3.) Press here to zoom

Additional Data

References

Go To: Top, Gas phase thermochemistry data, Condensed 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.

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

Brown, 1969
Brown, M.A.H., The heats of formation of selected cyanide and oxalate compounds, Diss. Abstr., 1969, 29, 3696. [all data]

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, 595-599. [all data]

Verkade, Hartman, et al., 1926
Verkade, P.E.; Hartman, H.; Coops, J., Calorimetric researches. X. Heats of combustion of successive terms of homologous series: dicarboxylic acids of the oxalic acid series, Rec. Trav. Chim. Pays/Bas, 1926, 45, 373-393. [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]

Verkade, Hartman, et al., 1924
Verkade, P.E.; Hartman, H.; Coops, J., Jr., Chemistry - The molecular heat of combustion of successive terms of homologous series, Kom. Med. Akad. Ueknschap. Proc., 1924, 27, 859-866. [all data]

Luff and Reed, 1982
Luff, B.B.; Reed, R.B., Low-temperature heat capacity and entropy of oxalic acid and of biuret, J. Chem. Eng. Data, 1982, 27, 290-292. [all data]

David, 1964
David, D.J., Determination of specific heat and heat of fusion by differential thermal analysis. Study of theory and operating parameters, Anal. Chem., 1964, 36, 2162-2166. [all data]

Satoh and Sogabe, 1939
Satoh, S.; Sogabe, T., The specific heats of some solid aliphatic acids and their ammonium salts and the atomic heat of nitrogen, Sci. Pap. Inst. Phys. Chem. Res. (Tokyo), 1939, 36, 97-105. [all data]

Parks, Kelley, et al., 1929
Parks, G.S.; Kelley, K.K.; Huffman, H.M., Thermal data on organic compounds. V. A revision of the entropies and free energies of nineteen organic compounds, J. Am. Chem. Soc., 1929, 51, 1969-1973. [all data]

Wilhoit and Shiao, 1964, 2
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, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Mass spectrum (electron ionization), References

• Symbols used in this document:
  

  Cp,gas	Constant pressure heat capacity of gas
  Cp,solid	Constant pressure heat capacity of solid
  S°solid,1 bar	Entropy of solid at standard conditions (1 bar)
  Tfus	Fusion (melting) point
  ΔHtrs	Enthalpy of phase transition
  ΔStrs	Entropy of phase transition
  ΔcH°solid	Enthalpy of combustion of solid at standard conditions
  ΔfH°solid	Enthalpy of formation of solid at standard conditions
  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
• The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database.
• Customer support for NIST Standard Reference Data products.