Die Kristallstruktur von Queitit, Pb₄Zn₂[SO₄|SiO₄|Si₂O₇]

Abstract

Abstract The crystal structure of the recently described new mineral Queitite was determined by X-ray diffraction. Queitite crystallizes monoclinic, space group P 2 1 , with a = 11.362(3), b = 5.266(1), c = 12.655(3) Å, β = 108.16(2)° and Z = 2. The structure was solved by Patterson and Fourier methods and refined to R = 0.033 for 2108 observed independent reflections. SiO 4 tetrahedra and Si 2 O 7 double tetrahedra are linked by ZnO 4 tetrahedra forming double sheets with five-membered rings. Between these sheets the Pb ions and isolated SO 4 tetrahedra are inserted. The coordination numbers of the Pb ions are discussed on the basis of the charge balance.