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organic compounds
The basic structural unit in the title compound, 2,2′-bi(1H-imidazol-3-ium) dichloride, C6H8N42+.2Cl−, consists of a planar diprotonated biimidazole moiety and two Cl− ions each connected to the dication via a pair of N-HCl bonds. The cation occupies a site of crystallographic 2/m symmetry with the twofold axis running through the connecting C2—C2′ bond and the middle of the ring C3—C3′ bonds. Contacts of Cl− ions with H atoms in adjacent units generate infinite layers in the (210) planes.