Experimental

R factor = 0.056; wR factor = 0.119; data-to-parameter ratio = 18.5. The title compound, C10H13N3O2S, crystallizes with two independent molecules (A and B) in the asymmetric unit. In the crystal, the A and B molecules are linked via pairs of N— H O and O—H S hydrogen bonds, forming dimers with R2 2(14) and R2 2(6) ring motifs. These dimers are linked via a pair of N—H S hydrogen bonds with an R22(8) ring motif, forming chains propagating along the c-axis direction. The crystal was refined as an inversion twin with a final BASF ratio of 0.54 (11):0.46 (11). Related literature For standard bond lengths, see: Allen et al. (1987). For hydrogen-bond motifs, see: Bernstein et al. (1995). For back-ground to thiosemicarbazones in coordination chemistry, see: Casas et al. (2000). For their biological applications, see: for example, Maccioni et al. (2003); Ferrari et al. (2000). For related structures, see: Kargar et al. (2010a,b)