Crystal structure of dilead(II) oxochromate(VI) oxotellurate(IV)

摘要

Reaction of chromium(III) precursors with TeO2 in PbF2/PbO melts in air led to oxidation of chromium(III) to chromium(VI), whereas tellurium remained its oxidation state of IV. In the resulting title compound, Pb2(CrO4)(TeO3), the two types of anions are isolated from each other, hence a double salt is formed. The two independent Pb²⁺ cations exhibit coordination number nine under formation of very distorted coordination polyhedra [bond-length range = 2.363 (6)–3.276 (7) Å]. The oxochromate(VI) and oxotellurate(IV) anions have tetra­hedral and trigonal–pyramidal configurations, respectively. In the crystal structure, (001) layers of metal cations alternate with layers of TeO3 ²⁻ and CrO4 ²⁻ anions along [001], forming a three-dimensional framework structure. Pb2(CrO4)(TeO3) is isotypic with its sulfate analogue Pb2(SO4)(TeO3) and is comparatively discussed.