In-situ high-pressure powder X-ray diffraction study of zirconium phosphate

The high-pressure structural chemistry of zirconium phosphate, Zr(HPO4)2·H2O, was studied using in-situ high-pressure diffraction and synchrotron radiation. The layered phosphate was studied under both hydrostatic and non-hydrostatic conditions and Rietveld refinement carried out on the resulting diffraction patterns. It was found that under hydrostatic conditions no uptake of additional water molecules from the pressure-transmitting medium occurred, contrary to what had previously been observed with some zeolite materials and a layered titanium phosphate. Under hydrostatic conditions the sample remained crystalline up to 10GPa, but under non-hydrostatic conditions the sample amorphized between 7.3 and 9.5GPa. The calculated bulk modulus, K 0 = 15.2GPa, showed the material to be very compressible with the weak linkages in the structure of the type Zr - O - P.