The crystal structures of bis(2-amino-5-methylpyridinium) tetrabromometallate(II):: Intermolecular interactions in (C6H9N2)2[MBr4];: M = Cd and Co

The crystallization and structures of a triclinic (henceforth T) (C6H9N2)(2)[CdBr4] and a monoclinic (henceforth M) of (C6H9N2)(2)[CoBr4] are reported. The crystal packing of both solids is analyzed and compared: both contain parallel chains of cations and stacks of anions. In both T and M, each [MBr4](2-) is hydrogen bonded non-symmetrically to surrounding cations in a ladder chains that run along b axis, with planar cations in both structures falling in parallel to the planes to anions. In T the cation chains are further involved in classical pi center dot center dot center dot pi stacking, while in M the cation chains show less significant stacking, with longer repeat distance.