Preparation and study of binary tungstates of rare earths and ammonium

Double tungstates NH4R(WO4)2xnH2O, where R=Sc, Y, La-Lu, have been synthesized. Individuality of the compounds obtained has been confirmed by the X-ray diffraction and IR spectroscopic analyses. Isomorphous series have been established for compounds of La-Sm (1st series) and Eu-Lu, Y (2nd series), as well as their isostructural character with respect to similar compounds of potassium and rubidium. Assignment has been made of vibration absorption bands of IR spectra of double tungstates of r.e.e. with ammonium. Decomposition of double tungdtates is studied thermographically. Final products of decomposition are simple tungstates of r.e.e. and tungsten trioxide for all salts (except for NH4La(WO4)2x1.5H2O)