Phthalazin-1(2H)-one

Abstract

The mol-ecule of the title compound, C8H6N2O, is almost planar, with a dihedral angle of 0.52 (7)° between the two rings. In the crystal structure, inter-molecular N - H⋯O, C - H⋯N and C - H⋯O hydrogen bonds and π-π inter-actions link the mol-ecules into a three-dimensional network. The π-π interaction occurs between the pyridazinone and benzene rings of the molecules at ( ) and ( ); the centroid-centroid distance is 3.588 (1) Å and the plane-plane separation is 3.434 Å. © International Union of Crystallography 2007.