ANHYDROUS 2,3,5,6-TETRAMETHYLPYRAZINIUM TETRAIODOCADMATE(II) AND ITS TRIHYDRATE, [C8H12N2(H)2][CDI4].XH2O (X=0, 3)

The structures of diprotonated 2,3,5,6-tetramethylpyrazinium tetraiodocadmate(II) as an anhydrous salt, (C8H14N2)[CdI4], (1), and as a trihydrate, (C8H14N2)[CdI4].3H2O, (2), have been determined. In both compounds the CdI4(2-) anion has slightly distorted tetrahedral geometry with Cd-I bonds ranging from 2.755 (2) to 2.793 (2) angstrom for (1) and from 2.751 (2) to 2.795 (2) angstrom for (2). In (1), the cations and anions are joined through hydrogen bonds to form layers in the ab plane. In (2) the cations are linked through hydrogen bonds to strings of three hydrogen-bonded water molecules to form infinite chains; there are no significant interactions involving the anions.