Water molecules insert into N—H⋅Cl— M hydrogen bonds while M —Cl⋅ X —C halogen bonds remain intact in dihydrates of halopyridinium hexachloroplatinates

The crystal structures of the 3‐halopyridinium hexachloroplatinate(IV) dihydrates (HPy X ‐3) 2 [PtCl 6 ]·2H 2 O [(1), X = Br; (2 a ), (2 b ), X = I] comprise networks in which the molecular components are linked via N—H⋅O and O—H⋅Cl—Pt hydrogen bonds and Pt—Cl⋅ X —C halogen bonds ( X = Br, I). The iodo derivative has been isolated in two polymorphic forms. Of particular interest to the understanding of the utility of the hydrogen bonds and M — X ⋅ X ′—C halogen bonds that propagate the networks in anhydrous salts of this type is that the water molecules insert exclusively into the putative N—H⋅Cl—Pt hydrogen bonds, while the Pt—Cl⋅ X ′—C halogen bonds remain undisrupted by the presence of water molecules.