1-(2,3,4-Trihydroxy-benzyl-idene)thio-semicarbazide

In the title mol-ecule, C(8)H(9)N(3)O(3)S, the thio-semicarbazide =N-NH-C(=S)-NH- fragment is twist a different degree of twist in the three independent mol-ecules [dihedral angles = 7.6 (1), 11.6 (1) and 20.7 (1)°]. Intra-molecular O-H⋯N and O-H⋯O hydrogen bonds occur. In the crystal, the hydr-oxy and amino groups are hydrogen-bond donors and the O-H⋯O, O-H⋯S and N-H⋯O hydrogen bonds generate a layer motif.