4-Chloro-2-nitro­benzoic acid–pyrazine (2/1)

In the title co-crystal, 2C(7)H(4)ClNO(4)·C(4)H(4)N(2), the pyrazine mol­ecule is located on an inversion centre, so that the asymmetric unit consists of one mol­ecule of 4-chloro-2-nitro­benzoic acid and a half-mol­ecule of pyrazine. The components are connected by O—H⋯N and C—H⋯O hydrogen bonds, forming a 2:1 unit. In the hydrogen-bonded unit, the dihedral angle between the pyrazine ring and the benzene ring of the benzoic acid is 16.55 (4)°. The units are linked by inter­molecular C—H⋯O hydrogen bonds, forming a sheet structure parallel to ([Image: see text]04). A C—H⋯O hydrogen-bond linkage is also observed between these sheets.