2,2′-Dithio­dianiline: a redetermination at 100 K

Structural studies of the title compound [systematic name: 2,2′-(disulfanedi­yl)dianiline], C(12)H(12)N(2)S(2), were previously performed at room temperature [Gomes de Mesquita (1967 ▶). Acta Cryst. 23, 671; Lee & Bryant (1970 ▶). Acta Cryst. B26, 1729; Ribar et al. (1975 ▶). Bull. Yugoslav. Crystallogr. Centre, A10, 68]. The results of the current redetermination allow a clarification of the nature of the intra- and inter­molecular N—H⋯S hydrogen bonding described in the literature for this compound. On cooling to 100 K, the unit cell contracts most in the c axis, and it changes rather less in the directions involving the strongly hydrogen-bonded chains, which are the a and b axes. In the crystal structure, N—H⋯N hydrogen bonds link neighbouring mol­ecules into two-dimensional frameworks parallel to the ab plane. An additional inter­molecular N—H⋯S hydrogen bond has also been established, based on freely refined H-atom positions. Inter­molecular C—H⋯π inter­actions further stabilize the crystal structure.