3-Benzyl-4-ethyl-1H-1,2,4-triazole-5(4H)-thione

The title compound, C11H13N3S, exists in the 5-thioxo tautomeric form. The benzene ring exhibits disorder with a refined ratio of 0.77 (2):0.23 (2) for components A and B with a common bridgehead C atom. The 1,2,4-triazole ring is essentially planar, with a maximum deviation of 0.002 (3) angstrom for the benzyl-substituted C atom, and forms dihedral angles of 88.94 (18) and 86.56 (49)degrees with the benzene rings of components A and B, respectively. The angle between the plane of the ethyl chain and the mean plane of 1,2,4-triazole ring is 88.55 (15)degrees and this conformation is stabilized by an intramolecular C-H center dot center dot center dot S contact. In the crystal, pairs of N-H center dot center dot center dot S hydrogen bonds link molecules into inversion dimers. pi-pi interactions are observed between the triazole and benzene rings, with centroid-centroid separations of 3.547 (4) and 3.544 (12) angstrom for components A and B, and slippages of 0.49 (6) and 0.58 (15) angstrom, respectively.