The nature of the interaction of RE(NO3)(3) (yttrium subgroup) with HF or NH4F

The nature of the interaction of RE(NO3)(3) of the yttrium subgroup with fluorinating agents (HF and NH4F) is considered. Depending on the pH of the solution as well as the fluorinating agent, it was found that compounds with the compositions of REF3 (using HF), (H3O)RE3F10 (NH4F, pH 0-2), NH4RE3F10 (NH4F, pH 3), and NH4RE2F7 (NH4F, pH 4) can be obtained by precipitation. The thermal stability of the obtained compounds and the morphology of the powder particles were established. All compounds obtained from the water environment contained adsorbed water, which was confirmed by FTIR spectroscopy and DSC/TG.