Hydrothermal Chemistry, Structures, and Luminescence Studies of Alkali Hafnium Fluorides

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• 作者：Christopher C. Underwood ; Colin D. McMillen ; Hongyu Chen ; Jeffery N. Anker ; Joseph W. Kolis
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：January 7, 2013
• 年：2013
• 卷：52
• 期：1
• 页码：237-244
• 全文大小：342K
• 年卷期：v.52,no.1(January 7, 2013)
• ISSN：1520-510X

文摘

This paper describes the hydrothermal chemistry of alkali hafnium fluorides, including the synthesis and structural characterization of five new alkali hafnium fluorides. Two ternary alkali hafnium fluorides are described: Li₂HfF₆ in space group P3̅1m with a = 4.9748(7) 脜 and c = 4.6449(9) 脜 and Na₅Hf₂F₁₃ in space group C2/m with a = 11.627(2) 脜, b = 5.5159(11) 脜, and c = 8.4317(17) 脜. Three new alkali hafnium oxyfluorides are also described: two fluoroelpasolites, K₃HfOF₅ and (NH₄)₃HfOF₅, in space group Fm3̅m with a = 8.9766(10) and 9.4144(11) 脜, respectively, and K₂Hf₃OF₁₂ in space group R3̅m with a = 7.6486(11) 脜 and c = 28.802(6) 脜. Infrared (IR) spectra were obtained for the title solids to confirm the structure solutions. Comparison of these materials was made based on their structures and synthesis conditions. The formation of these species in hydrothermal fluids appears to be dependent upon both the concentration of the alkali fluoride mineralizer solution and the reaction temperature. Both X-ray and visible fluorescence studies were conducted on compounds synthesized in this study and showed that fluorescence was affected by a variety of factors, such as alkali metal size, the presence/absence of oxygen in the compound, and the coordination environment of Hf⁴⁺.