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

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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 19F magic-angle spinning (MAS) and 19F–89Y CP MAS NMR techniques and applying the superposition model. The 19F 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.