Crystal structure of BaCa2MgSi2O8 and the photoluminescent properties activated by Eu2+

Rietveld refinements of X-ray powder diffraction data have confirmed the crystal structure of BaCa2MgSi2O8 prepared by a standard solid-state method. The final reliable factors were Rwp=10.91%, Rp=8.10%, RI=2.71%, and RF=1.14%. BaCa2MgSi2O8 crystallizes in the trigonal space group P3¯m1 (no. 164) with a=5.430(3) Å and c=6.807(2) Å. The oxide has a layered structure constructed from the unit layers built up by corner-sharing MgO6 octahedra and SiO4 tetrahedra. Ba and Ca atoms occupy the distinct crystallographic sites; Ba atom is sited in the interlayer space and Ca atom is embedded in the layer framework. This structure was not disrupted by doping of Eu2+ ions.