Preparation and crystal structure of two types of zirconium phosphates by hydrothermal reaction

Abstract

Single crystals of two types of zirconium phosphates, (NH4)2[Zr2(OH)2(PO4)2(HPO4)] and (NH4)Zr2(PO4)3 were prepared under hydrothermal condition using diethylene glycol as a solvent and their crystal structures were determined by using single crystal X-ray diffraction data. The former compound has the layer structure built up by corner-sharing ZrO6 octahedra and PO4 tetrahedra, and NH4+ ions were located in the interlayer space. This compound crystallized in the monoclinic system, space group C2/c (#15) and the unit cell parameters were a = 1.7093(4), b = 0.8748(2), c = 0.9216(2) nm and β = 103.69(2)° and the final R-factors were R = 0.066 and Rw = 0.121 for all 5982 reflections. This compound decomposed by releasing NH4+ ions in the interlayer above 300°C. The later compound has the cubic langbeinite-type structure in which NH4+ ions were located in the tunnel and the structural refinement by using single crystal X-ray diffraction data was performed for the first time. This compound crystallized in the cubic system, space group P213 (#198) and the unit cell parameters were a = 1.0198(2) nm and the final R-factors were R = 0.072 and Rw = 0.161 for all 1625 reflections. This compound also decomposed by releasing NH4+ ions above 800°C.