7-Hy-droxy-1,2,3,4-tetra-hydro-quinolin-2-one dihydrate

The asymmetric unit of the title compound, C(9)H(9)NO(2)·2H(2)O, comprises two independent organic mol-ecules and four water mol-ecules of crystallization. The heterocyclic rings are not planar: in one mol-ecule, the C atom bearing the O atom and the adjacent methyl-ene C atom are displaced by 0.320 (3) and 0.677 (3) Å, respectively, from the other eight atoms of the fused ring system. Equivalent values of 0.243 (3) and 0.659 (3) Å apply to the second mol-ecule. In the crystal, the components are linked by N-H⋯O and O-H⋯O hydrogen bonds, forming a three-dimensional network.