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.

The title compound, C 9 H 9 N 3 O 2 S, 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-HÁ Á ÁO hydrogen bonds are present. In the crystal, N-HÁ Á ÁO and N-HÁ Á ÁS interactions link the molecules into zigzag chains extending along the c-axis direction.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LR2116).
In (I), Fig. 1, the dihedral angle between the benzoyl unit (C1 -C7/O8 atoms, r.m.s. deviation = 0.068 Å) and thiobiuret group (N9 -N15 atoms) is 9.67 (13) °. The carbonyl-O8 and O11 atoms are positioned anti to each other, and S14 atom is also positioned anti to carbonyl-O11 atom. The molecular structure is stabilized by two intramolecular N-H···O hydrogen bonds ( Fig. 1 and Table 1). In the crystal packing, the intermolecular N-H···O and N-H···S interactions link the molecules into zigzag chains extending along the c axis (Fig. 2).

Experimental
Benzoyl chloride (48 ml, 58.1 g, 0.41mole) was added to warm solution of potassium thiocyanate (48.0 g, 0.49mole) in acetone (400 ml). The solution became milky white and yellow when the addition had been completed. The mixture was stirred for 3.5 h at 50 °C and left to cool to room temperature. The filtrate was heated to 55 °C for 5 h with urea (24.0 g, 0.40 mole). And the resulting solution was cooled to room temperature and then placed in an ice bath for several hours.
The cold mixture was filtered to give 1-benzoyl-4-thiobiuret as a bright yellow solid. The title compound (I) was obtained after recrystallization from its acetonitrile-methanol (10: 1) solution.

Refinement
H atoms of the NH and NH 2 groups were located in a difference Fourier map and refined freely [refined distances = 0.81 (3) -0.98 (4) Å]. Other H atoms were positioned geometrically and refined using a riding model, with C-H = 0.93 Å, and with U iso (H) = 1.2U eq (C).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1 0.33533 (17