Three isomorphous 2,6‐dibromopyridinium tetrabromidometallates: (C5H4Br2N)2[MBr4]·2H2O (M = Cu,Cd and Hg)

The structures of three isomorphous compounds, namely bis(2,6‐dibromopyridinium) tetrabromidocuprate(II) dihydrate, (C₅H₄Br₂N)₂[CuBr₄]·2H₂O, bis(2,6‐dibromopyridinium) tetrabromidocadmate(II) dihydrate, (C₅H₄Br₂N)₂[CdBr₄]·2H₂O, and bis(2,6‐dibromopyridinium) tetrabromidomercurate(II) dihydrate, (C₅H₄Br₂N)₂[HgBr₄]·2H₂O, show a crystal supramolecularity represented by M—Br...H—O—H...Br—M intermolecular interactions along with (π)N—H...OH₂ hydrogen‐bonding interactions forming layers connected via aryl–aryl face‐to‐face stacking of cations, leading to a three‐dimensional network. The anions have significantly distorted tetrahedral geometry and crystallographic C₂ symmetry. The stability of this crystal lattice is evidenced by the crystallization of a whole series of isomorphous compounds.