CRYSTAL-GROWTH AND STRUCTURE DETERMINATION OF POTASSIUM ZIRCONIUM-PHOSPHATE K2ZR(PO4)2

During the investigations of the system K2O-P2O5-ZrO2, a new potassium zirconium phosphate, K2Zr(PO4)2, was found. The crystals grown from melt solutions were merohedrally twinned. K2Zr(PO4)2 crystalizes in the space group P3bar with a = 5.176(1) angstrom, c = 9.011(2) angstrom, V = 209.1 angstrom-3, Z = 1, q(x) = 2.854 g/cm3. Its structure was refined to R = 0.029 and Rw = 0.041. K2Zr(PO4)2 shows a layer structure consisting of close packed ZrO6 layers perpendicular to the c-axis. The PO4 tetrahedra are slightly distorted. Further, the isostructural compound K2Sn(PO4)2 could be prepared.