Crystal structures of lanthanide and zirconium phosphates with general formula Ln0.33Zr2(PO4)3, where Ln=Ce, Eu, Yb

Crystal structures of synthetic phosphates Ce0.33Zr2(PO4)3, Eu0.33Zr2(PO4)3 and Yb0.33Zr2(PO4)3 have been refined by Rietveld method using powder diffraction data. Unit cell parameters: a=8.7419 (4), c=23.128 (2) Å; a=8.7659 (1), c=22.822 (1) Å; a=8.8078 (4), c=22.485 (3) Å, respectively; Z=6. Values of final R-factors in isotropic approximation: Rwp=4.00, Rwp=3.33, Rwp=4.12%, respectively. New space group P3¯c has been established for the compounds with general formula Ln0.33Zr2(PO4)3, where Ln=Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y. It has been confirmed that the synthetic phosphates with general formula Ln0.33Zr2(PO4)3 belong to the NZP (sodium zirconium phosphate) structure type.