2,2'-Sulfonyl-dipyrazine 4-oxide.

In the title compound, C(8)H(6)N(4)O(3)S, the dihedral angle between the pyrazine rings is 85.04 (1)°. In the crystal, mol-ecules are arranged along the a axis and are linked by C-H⋯N hydrogen bonds and pyrazine-pyrazine π-π inter-actions [centroid-centroid distance = 3.800 (1) Å, forming an infinite chain array. The chains are connected by C-H⋯O(oxide) hydrogen bonds into layers lying parallel to the ab plane. Along the c axis, the layers are stacked and linked through C-H⋯O(sulfon-yl) inter-actions, forming a three-dimensional network.