3-Cyclobutene-1,2-dione, 3,4-dihydroxy-

• Formula: C₄H₂O₄
• Molecular weight: 114.0563
• IUPAC Standard InChI: InChI=1S/C4H2O4/c5-1-2(6)4(8)3(1)7/h5-6H Copy

  
• IUPAC Standard InChIKey: PWEBUXCTKOWPCW-UHFFFAOYSA-N Copy
• CAS Registry Number: 2892-51-5
• 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: Squaric acid; Cyclobutenedione, dihydroxy-; Quadratic acid; 1,2-Dihydroxycyclobutene-3,4-dione; 1,2-Diketo-3,4-dihydroxycyclobutene; 3,4-Dihydroxy-3-cyclobutene-1,2-dione; 1,2-Dihydroxy cyclobutenedione; 1,2-Dihydroxy-3,4-cyclobutenedione; Cyclobutene-1,2-dione, 3,4-dihydroxy-; 3,4-Dihydroxy-cyclobutene-1,2-dione; NSC 125692
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• Information on this page:
  • Gas phase thermochemistry data
  • Condensed phase thermochemistry data
  • Phase change data
  • Mass spectrum (electron ionization)
  • References
  • Notes
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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: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Condensed 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 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

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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:
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Enthalpy of sublimation

Enthalpy of phase transition

Entropy of phase transition

Mass spectrum (electron ionization)

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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

Spectrum

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Additional Data

References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Mass spectrum (electron ionization), NIST Subscription Links, Notes

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

Sellers, 1971
Sellers, P., Enthalpies of formation of squaric acid and the corresponding diethyl ether, Acta Chem. Scand., 1971, 25, 2194-2198. [all data]

DeWit, Offringa, et al., 1983
DeWit, H.G.M.; Offringa, J.C.A.; De Kruif, C.G.; Van Miltenburg, J.C., Thermodynamic properties of molecular organic crystals containing nitrogen, oxygen and sulfur. III. Molar heat capacities measured by differential scanning calorimetry, Thermochim. Acta, 1983, 65, 43-51. [all data]

Barth, Helwig, et al., 1979
Barth, E.; Helwig, J.; Maier, H.D.; Mser, H.E.; Petersson, J., Specific heat of the two dimensional antiferroelectric squaric acid, Z. Phys., 1979, B34, 393-397. [all data]

De Wit, Van Miltenburg, et al., 1983
De Wit, H.G.M.; Van Miltenburg, J.C.; De Kruif, C.G., Thermodynamic properties of molecular organic crystals containing nitrogen, oxygen, and sulphur 1. Vapour pressures and enthalpies of sublimation, The Journal of Chemical Thermodynamics, 1983, 15, 7, 651-663, https://doi.org/10.1016/0021-9614(83)90079-4 . [all data]

Sellers, Holm, et al., 1971
Sellers, Peter; Holm, J.L.; Welch, B.J.; Prelesnik, A.; Zupancic, I.; Ehrenberg, L., Enthalpies of Formation of Squaric Acid and the Corresponding Diethyl Ether., Acta Chem. Scand., 1971, 25, 2194-2198, https://doi.org/10.3891/acta.chem.scand.25-2194 . [all data]

Pedley and Rylance, 1977
Pedley, J.B.; Rylance, J., , Computer Analysed Thermochemical Data: Organic and Organometallic Compounds, University of Sussex, Brighton, 1977. [all data]

Notes

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• Symbols used in this document:
  

  Cp,solid	Constant pressure heat capacity of solid
  ΔHtrs	Enthalpy of phase transition
  ΔStrs	Entropy of phase transition
  ΔcH°solid	Enthalpy of combustion of solid at standard conditions
  ΔfH°gas	Enthalpy of formation of gas at standard conditions
  ΔfH°solid	Enthalpy of formation of solid 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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