Violuric acid monohydrate: a second polymorph with more extensive hydrogen bonding

Acta Crystallogr C. 2007 Jun;63(Pt 6):o327-9. doi: 10.1107/S010827010701743X. Epub 2007 May 11.


Crystals of a second polymorph of violuric acid monohydrate [systematic name: pyrimidine-2,4,5,6(1H,3H)-tetrone monohydrate], C(4)H(3)N(3)O(4).H(2)O, have higher density and a more extensive hydrogen-bonding arrangement than the previously reported polymorph. Violuric acid and water molecules form essentially planar hydrogen-bonded sheets, which are stacked in an offset ...ABCABC... repeat pattern involving no ring-stacking interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Barbiturates / chemistry*
  • Crystallography, X-Ray
  • Hydrogen Bonding
  • Isomerism
  • Molecular Conformation


  • Barbiturates
  • violuric acid