4,5,6-Triamino-2-(methylsulfanyl)pyrimidine: pi-stacked hydrogen-bonded sheets of R2/2(8), R2/2(10) and R6/6(32) rings.

In the title compound, C5H9N5S, the three independent C-NH2 units are all somewhat pyramidal. The molecules are linked by a combination of one N-H...S and two N-H...N hydrogen bonds into sheets containing three types of ring motif, viz. R(2)(2)(8), R(2)(2)(10) and R(6)(6)(32), all of them centrosymmetric. Adjacent sheets are linked by a single pi-pi stacking interaction.