Local Structures of Solid Solutions Sr1-xYxF2+x (x=0...0.5) with Fluorite Structure Prepared by Sol-Gel and Mechanochemical Syntheses

Nanocrystalline Sr1-xYxF2+x samples (0 <= x <= 0.50) were prepared by fluorolytic sol-gel and mechanochemical syntheses using anhydrous HF or NH4F as fluorinating agents. This way, we compare the generated nanoparticular nonstoichiometric phases synthesized by two different routes. The obtained nonstoichiometric fluorite-type phases were studied using F-19 magic-angle spinning (MAS) and F-19-Y-89 CP MAS NMR techniques and applying the superposition model. The F-19 spectra of these phases can be fully explained by the distribution of Sr2+ and Y3+ cations around fluoride ions. These samples can serve as model compounds for a better structural understanding of fluorescent up- and down-converting systems.