Experimental Crystal data

disorder in main residue; R factor = 0.060; wR factor = 0.129; data-to-parameter ratio = 14.5. In the title compound, C17H10Cl2N4OS, the phenyl ring and the H atoms attached to the adjacent C atom are disordered over two positions, with refined site occupancies of 0.509 (8) and 0.491 (8). The planar 4H-1,3,4-thiadiazolo[2,3-c][1,2,4]-triazine ring system [maximum deviation = 0.048 (3) Å] forms dihedral angles of 76.9 (5), 74.9 (5) and 9.88 (12), respec-tively, with the major and minor parts of the disordered phenyl ring and with the dichloro-substituted benzene ring. In the crystal, pairs of C—H O hydrogen bonds link the molecules, forming inversion dimers with an R2 2(18) graph-set motif. A short S N contact of 2.801 (3) A ̊ is observed between the dimers. Related literature For applications of thiadiazole derivatives, see: Kurtzer (1965)