New phosphosilicates with nasicon structure type

New series of compounds, Bi1/3Pb1/6Zr2(PO4)8/3(SiO4)1/3 and Ln1/6Pb1/3Zr2(PO4)17/6(SiO4)1/6 with Ln = La, Nd, Sm, Eu, Gd, Tb, Er, Yb, have been synthesized via sol-gel routes and characterized by powder X-ray diffraction pattern techniques. Chemical analyses as well as the cell parameter evolution versus the ionic radii of rare earths are reported. The structure of the lanthanum-containing phase, which was refined using Rietveld methods, was found to crystallize in the trigonal system, space group R3.