Synthesis of Lanthanide Orthophosphate by Glycothermal Reaction

Abstract

Glycothermal reaction of acetate hydrates of lanthanide elements with triethyl phosphate in 1, 4-butanediol at 315°C afforded corresponding lanthanide orthophosphates (LnP04). The monoclinic modification of the phosphates was obtained from the acetates of La-Eu and the tetragonal one from Tb-Lu. Gadolinium acetate yielded a mixture of the tetragonal and monoclinic modifications, the former form of GdPO4 had been synthesized only by calcination of the monoclinic form at about 1700°C. With the decrease in the reaction temperature, the proportion of the tetragonal modification decreased. The monoclinic modification of TbPO. was also formed at the reaction temperature 225 °C together with the tetragonal form. The products were comprised of micro crystals (15~40nm). © 1993, The Chemical Society of Japan. All rights reserved.