Solid Solutions CaF2鈥揧F3 with Fluorite Structure Prepared on the Sol鈥揋el Route: Investigation by Multinuclear MAS NMR Spectroscopy

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• 作者：Thoralf Krahl ; Gudrun Scholz ; Erhard Kemnitz
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：September 11, 2014
• 年：2014
• 卷：118
• 期：36
• 页码：21066-21074
• 全文大小：427K
• ISSN：1932-7455

文摘

Nanoscaled Ca_1鈥?i>xY_xF_2+x (x = 0...0.40) was prepared on the new fluorolytic sol鈥揼el route using organic precursors and anhydrous HF. These nonstoichiometric fluorite-type phases were investigated using ¹⁹F MAS and ¹⁹F鈥?sup>89Y CP MAS NMR. Excess fluoride ions occur as point defects for x 鈮?0.01. For x > 0.01 excess fluoride ions start clustering. The ¹⁹F spectra of these phases can be fully explained by assuming a distribution of Ca²⁺ and Y³⁺ around fluoride ions. Y³⁺ is distributed within the crystal lattice of CaF₂, with higher concentrations near fluoride clusters. Two different coordination polyhedra for Y³⁺ are observed. The correlation between ¹⁹F and ⁸⁹Y signals was established.