Synthesis and thermal study of tris(ammonium) hexafluoro metallates(III) of some rare earths

Fluorination of oxides of rare earths using ammonium hydrogen fluoride at room temperature gave new compounds [NH 4 ] 3 MF 6 *nH 2 O, where M = Y, La, Nd, and Pr. In the case of cerium, [NH 4 ] 4 CeF 8 is formed. The course of thermal decomposition of all these compounds is studied by thermogravimetry/differential thermal analysis (TG/DTA) and X-ray powder diffraction (XRD). Keywords: hexafluoro metallates, rare earths, ammonium hydrogen fluoride, thermal decomposition, X-ray diffraction.