Benzoic acid–2,2′-biimidazole (2/1)

Abstract

In the title compound, C6H6N4·2C7H6O2, the asymmetric unit contains a half-molecule of biimidazole and one benzoic acid molecule. The unit cell contains two biimidazole molecules and four benzoic acid molecules, giving the reported 2:1 ratio of benzoic acid to biimidazole. The biimidazole molecule is located on an inversion center (passing through the central C—C bond). Strong N—H...O and O—H...N hydrogen bonds link the benzoic acid molecules with the neutral biimidazole molecules, which lie in planar sheets. In the crystal packing, the parallel sheets are related by a twofold rotation axis and an inversion centre, respectively, forming an interwoven three-dimensional network via weak C=O...π intermolecular interactions between neighboring molecules.