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

R factor = 0.029; wR factor = 0.081; data-to-parameter ratio = 19.0. In the title co-crystal, 2C7H4ClNO4C4H4N2, 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 (104). A C—H O hydrogen-bond linkage is also observed between these sheets. Related literatur