Gadolinium orthophosphate weinschenkite type and phase change in rare earth orthophosphates

Some properties of rare earth orthophosphates have been determined by means of synthesis, X-ray diffraction, infrared absorption spectra, and Raman sp ectra measurements. The results are: (1) a synthesis of new compounds GdPO4 . 2H(2)O weinschenkite type, (2) the salt readily lost its water and change d from the weinschenkite to the xenotime form at about 300 degrees C in air , (3) the change phase in rare earth orthophosphates showed that the weinsc henkite phase can give rise to rhabdophane or xenotime phases, and (4) the orthorhombic form DyPO4. 1.5H(2)O is explainable in terms of a mixture of r habdophane and xenotime-structured material.