Synthesis and characterization of mixed fluorides Y1-xCa2+1.5xF7 (-1.33 <=x <= 1.0)

In this paper, we report on the synthesis and characterization of the Y1-xC a2+1.5xF7 (-1.33 less than or equal to x less than or equal to 1.0) compoun ds and the phase equilibria in the CaF2-YF3 system, in the continuation of our earlier studies on Sr and Ba analogues. It was found that the solubilit y limit of YF3 in the CaF2 lattice is about 33 mol% as compared to about 25 mol% of YF3 in BaF2 and SrF2. The CaF2-YF3 system shows the formation of a n ordered cubic superstructure after the solubility limit. A hexagonal tyso nite type phase separates out beyond 41 mol% of YF3. A single phasic tysoni te type product was obtained at the composition with about 75 mol% of YF3, i.e., Y1.9Ca0.65F7. (C) 2000 Elsevier Science Ltd.