Incorporation of Sulfate or Selenate Groups into Oxotellurates(IV): III. Compounds with Magnesium or Zinc

The mixed oxochalcogenate compounds Mg 2 (SO 4 )(TeO 3 )(H 2 O), Mg 3 (SO 4 )(TeO 3 )(OH) 2 (H 2 O) 2 , Zn 2 (SeO 4 )(TeO 3 ), and Zn 4 (SO 4 )(TeO 3 ) 3 were obtained under hydrothermal conditions (210 °C, autogenous pressure). Structure analyses using single‐crystal X‐ray data revealed tellurium in all four compounds to be present in oxidation state +IV, whereas sulfur or selenium atoms exhibit an oxidation state of +VI. In the crystal structures of the two magnesium compounds, [MgO 5 (H 2 O)] octahedra [Mg 2 (SO 4 )(TeO 3 )(H 2 O) structure, isotypic with the Co and Mn analogues] or [MgO 4 (OH) 2 ] and [MgO 4 (OH) 2 (H 2 O) 2 ] octahedra [Mg 3 (SO 4 )(TeO 3 )(OH) 2 (H 2 O) 2 structure, novel structure type] as well as trigonal‐pyramidal TeO 3 2– anions make up metal oxotellurate sheets, which are bridged by SO 4 2– anions. The polar crystal structure of Zn 2 (SeO 4 )(TeO 3 ) is isotypic with Zn 2 (MoO 4 )(TeO 3 ) and consists of [ZnO 4 ] tetrahedra, [ZnO 6 ] octahedra, SeO 4 2– and TeO 3 2– anions as principal building units that are connected into a framework structure. Such a structural arrangement, with basically the same coordination polyhedra as in Zn 2 (SeO 4 )(TeO 3 ) but with SO 4 2– instead of SeO 4 2– anions, is also found in the tellurium‐rich compound Zn 4 (SO 4 )(TeO 3 ) 3 that crystallizes in a novel structure type.