Acta Cryst. (2004). E60, o2219-o2220  [ doi:10.1107/S1600536804027527 ]

Pyridazine-3,6-dicarboxylic acid monohydrate

W. Starosta and J. Leciejewicz

Abstract: The title compound, C₄H₄N₂O₄·H₂O, is a triclinic polymorphic form of pyridazine-3,6-dicarboxylic acid monohydrate. The dihedral angles between the planes of the carboxylic acid groups and the planar pyrazine ring are 2.0 (2) and 5.6 (2)°. The acid and water molecules form almost planar sheets connected by hydrogen bonds, with OO distances ranging from 2.5143 (14) to 2.7330 (16) Å and an ON distance of 2.8234 (18) Å. The shortest distance between two adjacent sheets is 3.2 (1) Å, indicating van der Waals-type interactions.

Online 6 November 2004

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