A monoclinic polymorph of 1-benzoyl-4-thio­biuret

The title compound, C₉H₉N₃O₂S, is a monoclinic (C2/c) polymorph of the previously reported triclinic structure [Kang (2013). Acta Cryst. E69, o1327]. The mol­ecule is almost planar with an r.m.s. deviation of 0.069 Å from the mean plane of all non-H atoms. The benzoyl and terminal thio­urea fragments adopt a transoid conformation with respect to the central carbonyl O atom. Two intra­molecular N—H...O hydrogen bonds are present. In the crystal, N—H...O and N—H...S inter­actions link the mol­ecules into zigzag chains extending along the c-axis direction.