The Melt of Sodium Nitrate as a Medium for the Synthesis of Fluorides

Abstract

The preparation of NaLnF₄ complexes, LnF₃ (Ln = La, Ce, Y) rare earth binary fluorides, CaF₂ and SrF₂ alkali earth fluorides, as well as mixtures of these compounds from their nitrates dissolved in molten NaNO₃ has been studied in order to select the ideal solvent for fluoride synthesis by spontaneous crystallization from flux. Sodium fluoride (NaF) was used as a fluorinating agent. The results of our experiments have confirmed that NaNO₃ melt is one of the most promising media for precipitating said inorganic fluoride materials within a broad temperature range (300–500 °С). Also, in contrast with precipitation/co-precipitation from aqueous solutions, our syntheses have resulted in obtaining equilibrium phases only.