Co-precipitation of yttrium and barium fluorides from aqueous solutions

Synthesis of CaF2–YF3 nanopowders by coprecipitation from aqueos solutions

“…3) confirmed that the precipitated nanoparticles were actually of the small sizes. Chemical analyses of both types, X-ray spectroscopy and AES (Table 1, also see Supplemental Information), have shown that the metal ratios in the formed solid precipitates were close to the corresponding ratios in the starting aqueous solutions/mixtures even if the observed ratio differences were a little bit larger than in the case of the previously studied SrF 2 -YF 3 [53] and BaF 2 -YF 3 [49] systems.…”

“…% RF 3 ) and possess ordered fluorite-type structures (such ordered phases are usually thermodynamically stable at the lower temperatures). The other previously studied MF 2 -RF 3 systems (e.g., SrF 2 -YF 3 [53], BaF 2 -YF 3 [49], BaF 2 -CeF 3 [52]) with M = Sr and Ba have exhibited different features: each of these systems had the concentration ranges, where ordered fluorite-type phases were observed under equilibrium conditions at the higher temperatures, the unordered solid solutions were formed. Currently, it is hard to find a reasonable explanation for the different results for calcium fluoride systems.…”

“…Specimens in the CaF 2 -YF 3 system were prepared by co-precipitation from aqueous solutions in polypropylene reactors according to previously-described procedures [4,49,53,54]. 0.2 Mol/L aqueous nitrate solutions in double distilled water were vigorously mixed with magnetic stirring bar and then added dropwise under continued stirring to a 2-fold excess of 5 vol.% aqueous HF.…”

“…Low-temperature and soft chemistry syntheses of nanofluorides (e.g, mechanochemical [40,41], sol-gel [24], solvothermal [42] methods and some other techniques [35]) are especially prominent because of their technological advantages. Recently, we have successfully used our coprecipitation from aqueous solutions methods for nanofluoride preparations [34,35,[43][44][45][46][47][48], including our systematic studies of phase formations in the BaF 2 -YF 3 [49], BaF 2 -BiF 3 [50], BaF 2 -ScF 3 [51], BaF 2 -CeF 3 [52], SrF 2 -YF 3 [53] and CaF 2 -HoF 3 [54] systems. We have observed varieties of phase fields in the studied MF 2 -YF 3 and NaF-RF 3 systems, including non-equilibrium phases with wide areas of homogeneity; we have also observed the absence of the ordered phases that exist under higher temperature equilibrium conditions [4].…”

The solubility of sodium and potassium fluorides in strontium fluoride

“…In order to identify the region of solid solutions based on SrF 2 , in addition to the classic techniques of research, we used the technique of nanotechnology: previous investigations have shown that under low temperature syntheses, as a rule, non-equilibrium phases of variable composition are formed, with the width of the homogeneity region of solid solutions based on components often correspond to the limiting width of the high-temperature solid solutions, or even exceed it [1,6,10,[23][24][25].…”