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
- IUPAC Standard InChIKey: PWEBUXCTKOWPCW-UHFFFAOYSA-N
- 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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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
| Quantity | Value | Units | Method | Reference | Comment |
|---|---|---|---|---|---|
| ΔsubH° | 154.3 | kJ/mol | N/A | De Wit, Van Miltenburg, et al., 1983 | AC |
| ΔsubH° | 84. ± 17. | kJ/mol | E | Sellers, Holm, et al., 1971 | See also Pedley and Rylance, 1977.; AC |
| ΔsubH° | 84. ± 17. | kJ/mol | E | Sellers, 1971 | ALS |
Enthalpy of sublimation
| ΔsubH (kJ/mol) | Temperature (K) | Method | Reference | Comment |
|---|---|---|---|---|
| 152.5 | 486. | ME,TE | De Wit, Van Miltenburg, et al., 1983 | Based on data from 469. - 499. K.; AC |
Enthalpy of phase transition
| ΔHtrs (kJ/mol) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
|---|---|---|---|---|---|
| 0.300 | 372.2 | crystaline, II | crystaline, I | DeWit, Offringa, et al., 1983 | DH |
| 0.347 | 373.57 | crystaline, II | crystaline, I | Barth, Helwig, et al., 1979 | DH |
Entropy of phase transition
| ΔStrs (J/mol*K) | Temperature (K) | Initial Phase | Final Phase | Reference | Comment |
|---|---|---|---|---|---|
| 0.8 | 372.2 | crystaline, II | crystaline, I | DeWit, Offringa, et al., 1983 | DH |
| 0.93 | 373.57 | crystaline, II | crystaline, I | Barth, Helwig, et al., 1979 | DH |
References
Go To: Top, Phase change data, Notes
Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.
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]
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]
Notes
Go To: Top, Phase change data, References
- Symbols used in this document:
ΔHtrs Enthalpy of phase transition ΔStrs Entropy of phase transition 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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