Acridine 0.75-hydrate

The title compound, C(13)H(9)N·0.75H(2)O was obtained during a study of the polymorphic system of acridine, by slow evaporation from an ethanol–water solution. There are two acridine mol­ecules (indicated by I and II, respectively) and one and a half water mol­ecules in the asymmetric unit. The half-mol­ecule of water is located on a crystallographic twofold axis. The crystal structure is built up from two threads of mol­ecule II sewn together with water mol­ecules through O—H⋯O and O—H⋯N hydrogen bonds from one side and with π–π inter­actions [centroid–centroid distance = 3.640 (3) and 3.7431 (3) Å] between overlapping mol­ecules II on the other side. Mol­ecule I is attached to this thread from both sides by C—H⋯O hydrogen bonds. The threads are connected to each other by π–π inter­actions [centroid–centroid distances = 3.582 (3) and 3.582 (3) Å] between the inner side of mol­ecule I and stabilized by a C—H⋯π inter­action on the other side of mol­ecule I. This thread with rows of mol­ecule I hanging on its sides is generated by translation perpendicular to the a axis.