A Novel Method for Preparing High Purity Anhydrous LaF ₃ and YF ₃ by Reaction of Rare Earth Complex With Ammonia Hydride Fluoride

ABSTRACT In this paper, a novel synthetic route is presented for the production of 99.99% high‐purity anhydrous rare earth fluoride. First, organic system was used to produce high‐purity diphenylpropanedione salt with hydrated rare earth salt as raw material through complex reaction, followed by recrystallization, and high‐temperature vacuum drying to remove water of crystallization. Then, the resulting complex salt was reacted with ammonium hydride fluoride to prepare high‐purity anhydrous rare earth fluoride. This method avoids the challenges associated with traditional dry methods, such as harsh reaction conditions and the easy introduction of impurities, as well as the high oxygen content and filtration difficulties of wet methods. The purity, oxygen content, and composition of the prepared rare earth fluoride products were analyzed using thermal analyzers, scanning electron microscopy, X‐ray diffraction, inductively coupled plasma mass spectrometry, and an oxygen analyzer. The results demonstrated that this method produces rare earth fluoride with high purity, anhydrous properties, low oxygen content, and excellent crystallinity. This approach represents a green, efficient, and innovative preparation method for rare earth fluoride and offers a new pathway for the production of high‐purity rare earth fluoride compounds.