Lithium barium silicate, Li2BaSiO4, from synchrotron powder data

Abstract

The structure of lithium barium silicate, Li(2)BaSiO(4), has been determined from synchrotron radiation powder data. The title compound was synthesized by high-temperature solid-state reaction and crystallizes in the hexagonal space group P6(3)cm. It contains two Li atoms, one Ba atom (both site symmetry ..m on special position 6c), two Si atoms [on special positions 4b (site symmetry 3..) and 2a (site symmetry 3.m)] and four O atoms (one on general position 12d, and three on special positions 6c, 4b and 2a). The basic units of the structure are (Li(6)SiO(13))(5-) units, each comprising seven tetrahedra sharing edges and vertices. These basic units are connected by sharing corners parallel to [001] and through sharing (SiO(4))(4-) tetrahedra in (001). The relationship between the structures and luminescence properties of Li(2)SrSiO(4), Li(2)CaSiO(4) and the title compound is discussed.