Incorporation of Sulfate or Selenate Groups into Oxotellurates(IV): II. Compounds with Divalent Lead

Four mixed oxochalcogenate compounds in the systems Pb^II/X^VI/Te^IV/O/(C), (X^VI = S and Se) were obtained as minority phases under hydrothermal conditions (210 °C, one week). Their compositions as determined on the basis of single‐crystal X‐ray diffraction data are Pb₃(SeO₄)(TeO₃)₂, Pb₇O₄(SeO₄)₂(TeO₃), Pb₅(SeO₄)₂(TeO₄)(CO₃), and Pb₂(SO₄)(TeO₃). All crystal structures are centrosymmetric, and in each case the oxochalcogenate anions are isolated from each other. The Pb²⁺ cations exhibit distorted coordination polyhedra with coordination numbers ranging from six to ten, in the majority of cases with a “one‐sided” coordination by oxygen atoms. The presence of the very rare square‐pyramidal Te^IVO₄^4– anion distinguishes the structure of Pb₅(SeO₄)₂(TeO₄)(CO₃) from the other structures, where the oxotellurate(IV) anions exist in the TeO₃^2– trigonal‐pyramidal configuration.