Zur Kristallchemie des ersten Blei-Zink-Silicium-Telluroxids: PbZn_4SiTeO_(10)

摘要

Single crystals of the new lead zinc silicon tellurium oxide PbZn_4SiTeO_(10) have been prepared by solid state reaction in air. The compound is colourless and crystallizes in orthorhombic symmetry space group D_(2n)~(16) Pnma, with the cell parameters: a = 6.542 (5), b = 15.642 (4), c = 8.280 (4) A, Z = 4. The structure has been determined from a single crystal X-ray study and refined to the conventional values R = 0.032 and wR(F~2) = 0.050. Zn~(2+) and Si~(4+) show tetrahedral and Te~(6+) octahedral coordination by O~(2-). The crystal structure is dominated by a _(infinity)~3 [Zn_4O_(10)]~(12-) framework with isolated TeO_6~(6+) and SiO_4~(4+) polyhedra. Pb~(2+) ions are incorporated in the network. The centres of negative charge of the lone pairs of Pb~(2+) are estimated by calculations of the Coulomb term of the lattice energy.