Phase formation in LaF3-NaGdF4, NaGdF4-NaLuF4, and NaLuF4-NaYF4 systems: Synthesis of powders by co-precipitation from aqueous solutions

作者：Kuznetsov Sergei V; Ovsyannikova Anna A; Tupitsyna Ekaterina A; Yasyrkina Daria S; Voronov Valery V; Batyrev Nikolay I; Iskhakova Liudmila D; Osiko Vyacheslav V; Fedorov Pavel P^*

来源：Journal of Fluorine Chemistry, 2014, 161: 95-101.

DOI：10.1016/j.jfluchem.2014.02.011

• Rare earth fluorides
• Sodium fluoride
• Phase diagrams
• Fluorite
• Gagarinite
• Tysonite

Detailed studies of LaF3-NaGdF4, NaGdF4-NaLuF4, and NaLuF4-NaYF4 systems have revealed that LaF3-NaGdF4 system precipitates, formed in aqueous media, contained gagarinite-type NaGd1-xLaxF4 (x <= 0.0625) solid solution, tysonite-type La1-xGdxF3 (x <= 0.50) phase, and cubic fluorite-type NaGdF4-based phase, whereas NaGdF4-NaLuF4 precipitates contained hexagonal gagarinite-type (x <= 0.25) and cubic fluorite-type (x >= 0.675) NaGd1-xLuxF4 solid solutions. Furthermore, there were continuous series of single-phase cubic fluorite-type NaLuF4-NaYF4 solid solutions formed in the third investigated system. Crystallization of Na0.5-xLu0.5+xF2+2x solid solutions from aqueous media occurred in an incongruent manner; the use of 5-fold excess of NaF led to precipitation of NaLuF4 (x = 0) with almost stoichiometric composition.

• 出版日期2014-5