High-Temperature, High-Pressure Hydrothermal Synthesis and Characterization of a Salt-Inclusion Mixed-Valence Uranium(V,VI) Silicate: [Na9F2][(UVO2)(UV

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• 作者：Yu-Chih Chang ; Wen-Jung Chang ; Sophie Boudin ; Kwang-Hwa Lii
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：June 17, 2013
• 年：2013
• 卷：52
• 期：12
• 页码：7230-7235
• 全文大小：401K
• 年卷期：v.52,no.12(June 17, 2013)
• ISSN：1520-510X

文摘

A salt-inclusion mixed-valence uranium(V,VI) silicate, [Na₉F₂][(U^VO₂)(U^VIO₂)₂(Si₂O₇)₂], was synthesized under hydrothermal conditions at 585 掳C and 160 MPa and structurally characterized by powder and single-crystal X-ray diffraction (XRD). The valence states of uranium were established by U 4f X-ray photoelectron spectroscopy (XPS). The structure contains two-dimensional (2D) sheets of uranyl disilicate with the composition [UO₂Si₂O₇], which are connected by U(1)^VO₆ tetragonal bipyramids to form thick layers. The Na⁺ cations are located at sites in the intralayer and interlayer regions. In addition to Na⁺ cations, the interlayer region also contains F^{鈥?/sup> anions such that infinite chains with the formula FNa_1/1Na_4/2 are formed. The same type of chain was observed in K₂SnO₃. The title compound is not only the first example of salt-inclusion metal silicate synthesized under high-temperature, high-pressure hydrothermal conditions, as well as the first salt-inclusion mixed-valence uranium silicate, but it is also the first mixed-valence uranium(V,VI) silicate in the literature. Crystal data: [Na₉F₂][(UVO₂)(UVIO₂)₂(Si₂O₇)₂], triclinic, P1̅ (No. 2), a = 5.789(1) 脜, b = 7.423(2) 脜, c = 12.092(2) 脜, 伪 = 90.75(3)掳, 尾 = 96.09(3)掳, 纬 = 90.90(3)掳, V = 516.5(2) 脜3, Z = 1, R₁ = 0.0241, and wR₂ = 0.0612.}