A simple compound with an unexpectedly complex structure: 4-pyridone 6/5-hydrate

The crystal structure of the title compound, C5H5NO .6/5H(2)O,contains five independent molecules of pyridone and six independent water molecules. The space group is P2(1), but four of the pyridones and four waters correspond closely to P2(1)/n. The packing involves two layers; one consists of head-to-tail chains of pyridone molecules 1-4 linked by N-H . . .O hydrogen bonds, and a second layer involves all the waters and the fifth pyridone. The layers are linked by hydrogen bonds from water to pyridone oxygen. The four water O atoms that accept only one classical hydrogen bond have their environment completed by C-H . . .O interactions.