Tamarixetin monohydrate

In the title compound, 3,5,7,3'-tetrahydroxy-4'-methoxyfavone monohydrate [ or 3,5,7-trihydroxy-2-(3-hydroxy-4-methoxyphenyl)-4H-1-benzopyran-4-one mon ohydrate], C16H12O7. H2O, there are two independent molecules in the asymme tric unit, linked through OH groups to form an O-H ... O hydrogen-bonded di mer. The benzopyran rings are slightly distorted from planarity; in one of the molecules the phenyl ring is coplanar with the pyrone ring, while in th e other it is twisted by 4.8 (1)degrees. The hydroxyl groups are involved i n various O-H ... O and C-H ... O hydrogen bonds and the molecules are stac ked parallel to the (220) plane.