Synthesis, structure and luminescence of new Ca3SnSi2O9

Ca3SnSi2O9 was prepared by solid state reaction of CaCO3, SnO2 and SiO2. The crystal structure [a = 732.83(7), b = 1007.43(8), c = 1043.88(9)pm, β = 91.064(2)°, monoclinic, P21c, Z = 4, RP = 2.48, Rwp = 3.27%] has been determined with the Rietveld method from neutron powder diffraction data. The structure has isolated pairs of edge sharing Sn(IV)O6 octahedra. These Sn2O10 groups show an efficient luminescence with a very large Stokes shift.