2,2'-Bi(1H-imidazolium) Dichloride

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-H...Cl 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.

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