Barbituric acid

• Formula: C₄H₄N₂O₃
• Molecular weight: 128.0862
• IUPAC Standard InChI: InChI=1S/C4H4N2O3/c7-2-1-3(8)6-4(9)5-2/h1H2,(H2,5,6,7,8,9) Copy

  
• IUPAC Standard InChIKey: HNYOPLTXPVRDBG-UHFFFAOYSA-N Copy
• CAS Registry Number: 67-52-7
• Chemical structure:
  This structure is also available as a 2d Mol file
• Species with the same structure:
  • Barbituric acid
• Other names: 2,4,6(1H,3H,5H)-Pyrimidinetrione; Malonylurea; Pyrimidinetrione; Urea, N,N'-(1,3-dioxo-1,3-propanediyl)-; 2,4,6-Pyrimidinetriol; 2,4,6-Trihydroxypyrimidine; 2,4,6-Trioxohexahydropyrimidine; 6-Hydroxyuracil; 2,4,6-Pyrimidinetrione(1H,3H,5H)
• Information on this page:
  • Condensed phase thermochemistry data
  • Phase change data
  • Gas phase ion energetics data
  • References
  • Notes
• Other data available:
  • Gas phase thermochemistry data
  • Reaction thermochemistry data
  • IR Spectrum
  • Mass spectrum (electron ionization)
  • UV/Visible spectrum
• Options:
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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 by: William E. Acree, Jr., James S. Chickos

Enthalpy of sublimation

Enthalpy of fusion

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

Ionization energy determinations

De-protonation reactions

C₄H₃N₂O₃^- +  =

By formula: C₄H₃N₂O₃^- + H⁺ = C₄H₄N₂O₃

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.

Soldatova, Kabo, et al., 1990
Soldatova, T.V.; Kabo, G.Ya.; Kozyro, A.A.; Frenkel, M.L., Thermodynamic properties and tautomerism of barbituric acid, Russ. J. Phys. Chem. (Engl. Transl.), 1990, 64, 177-180. [all data]

Lemoult, 1904
Lemoult, M.P., Remarques sur une serie recenie de determinations calorimetriques, Compt. Rend., 1904, 663-635. [all data]

Soldatova, Kabo, et al., 1990, 2
Soldatova, T.V.; Kabo, G.Ya.; Kozyro, A.A.; Frenkel, M.L., Thermodynamic properties and tautomerism of barbituric acid, Zhur. Fiz. Khim., 1990, 64(2), 336-343. [all data]

Koshchenko, Ismailov, et al., 1985
Koshchenko, V.I.; Ismailov, T.S.; Potekhin, V.M.; Razikov, K.Kh., Thermodynamic functions of barbituric acid, Zhur. Prikl. Khim. (Leningrad), 1985, 58, 445-456. [all data]

Brunetti and Piacente, 1999
Brunetti, B.; Piacente, V., Sublimation Enthalpies Study for Barbituric, Tiobarbituric, and Selenobarbituric Acids from Their Vapor Pressure Measurements, J. Chem. Eng. Data, 1999, 44, 4, 809-812, https://doi.org/10.1021/je980300k . [all data]

Zielenkiewicz, Perlovich, et al., 1999
Zielenkiewicz, X.; Perlovich, G.L.; Wszelaka-Rylik, M., Journal of Thermal Analysis and Calorimetry, 1999, 57, 1, 225-234, https://doi.org/10.1023/A:1010179814511 . [all data]

Soldatova, Kabo, et al., 1990, 3
Soldatova, T.V.; Kabo, G.Ya.; Kozyro, A.A.; Frenkel, M.L., Thermodynamic properties and tautomerism of barbituric acid, Zh. Fiz. Khim., 1990, 64, 2, 336. [all data]

Roux, Temprado, et al., 2008
Roux, Maria Victoria; Temprado, Manuel; Notario, Rafael; Foces-Foces, Concepcion; Emel'yanenko, Vladimir N.; Verevkin, Sergey P., Structure-Energy Relationship in Barbituric Acid: A Calorimetric, Computational, and Crystallographic Study, J. Phys. Chem. A, 2008, 112, 32, 7455-7465, https://doi.org/10.1021/jp803370u . [all data]

Dougherty, Younathan, et al., 1978
Dougherty, D.; Younathan, E.S.; Voll, R.; Abdulnur, S.; McGlynn, S.P., Photoelectron spectroscopy of some biological molecules, J. Electron Spectrosc. Relat. Phenom., 1978, 13, 379. [all data]

Cumming and Kebarle, 1978
Cumming, J.B.; Kebarle, P., Summary of gas phase measurements involving acids AH. Entropy changes in proton transfer reactions involving negative ions. Bond dissociation energies D(A-H) and electron affinities EA(A), Can. J. Chem., 1978, 56, 1. [all data]

Notes

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• Symbols used in this document:
  

  Cp,solid	Constant pressure heat capacity of solid
  S°solid,1 bar	Entropy of solid at standard conditions (1 bar)
  ΔcH°solid	Enthalpy of combustion of solid at standard conditions
  ΔfH°solid	Enthalpy of formation of solid at standard conditions
  ΔfusH	Enthalpy of fusion
  ΔrG°	Free energy of reaction at standard conditions
  ΔrH°	Enthalpy of reaction at standard conditions
  ΔsubH	Enthalpy of sublimation

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