Organically templated linear and layered cadmium sulfatesElectronic supplementary information (ESI) available: powder diffraction data for IV, view of I down the a-axis, the structure of II in the ac-plane and a polyhedral view of IV in the ab-plane. See http://www.rsc.org/suppdata/dt/b2/b204482j/

Abstract

By reacting cadmium salts with H2SO4 in the presence of organic amines or directly with amine sulfates under hydrothermal conditions, it has been possible to prepare three linear cadmium sulfates of linarite topology, with the compositions [H3N(CH2)2NH3]2[CdCl2(SO4)][SO4]·H2O, I, [HN(CH2)6NH][CdBr2(SO4)], II, [HN(CH2)6NH][CdCl2(SO4)], III. A layered cadmium sulfate of composition [H3N(CH2)3NH3][Cd2(H2O)2(SO4)3], IV, has also been obtained. These sulfates are the first examples of a family of organically templated metal sulfates with interesting structural features. In the linarite chains, the CdX4O2 (X = Cl, Br) octahedron shares two trans-edges to form an [Mφ4] (φ = anionic ligand) chain decorated by the SO4 tetrahedron that adopts a staggered arrangement on either side of the chain. IV is constructed by the fusion of four-membered ring ladders involving edge sharing between the sulfate tetrahedron and metal octahedron. IV appears to be the first member of a family of organically templated metal sulfates containing an octahedral–tetrahedral 2D net wherein the sulfate tetrahedron is connected at all four corners.