High-Temperature, High-Pressure Hydrothermal Synthesis, Crystal Structures, and Spectroscopic Studies of a Uranium(IV) Phosphate (Na10U2P6O24) and the Isoty

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• 作者：Yu-Hsien Lai ; Yu-Chih Chang ; Tsz-Fung Wong ; Wan-Ju Tai ; Wen-Jung Chang ; Kwang-Hwa Lii
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：December 2, 2013
• 年：2013
• 卷：52
• 期：23
• 页码：13639-13643
• 全文大小：315K
• 年卷期：v.52,no.23(December 2, 2013)
• ISSN：1520-510X

文摘

A uranium(IV) phosphate, Na₁₀U₂P₆O₂₄, was synthesized under hydrothermal conditions at 570 掳C and 160 MPa and structurally characterized by single-crystal X-ray diffraction. The valence state of uranium was established by UV鈥搗is and U 4f X-ray photoelectron spectroscopy. The powder sample has a second-harmonic-generation signal, confirming the absence of a center of symmetry in the structure. The structure contains UO₈ snub-disphenoidal polyhedra that are linked to monophosphate tetrahedra by vertex and edge sharing such that a three-dimensional framework with intersecting 12-sided circular and rectangular channels is formed. All 10 sodium sites are situated inside the channels and are fully occupied. This is the first uranium(IV) phosphate synthesized under high-temperature, high-pressure hydrothermal conditions. The isotypic cerium(IV) phosphate, Na₁₀Ce₂P₆O₂₄, was also synthesized under the same hydrothermal conditions. It is the first structurally characterized Ce(IV) phosphate with a P/Ce ratio of 3. Crystal data of Na₁₀U₂P₆O₂₄: orthorhombic, P2₁2₁2₁ (No. 19), a = 6.9289(3) 脜, b = 16.1850(7) 脜, c = 18.7285(7) 脜, V = 2100.3(2) 脜³, Z = 4, R₁ = 0.0304, and wR₂ = 0.0522. Crystal data of Na₁₀Ce₂P₆O₂₄: orthorhombic, P2₁2₁2₁ (No. 19), a = 6.9375(14) 脜, b = 16.215(3) 脜, c = 18.765(4) 脜, V = 2111.0(7) 脜³, Z = 4, R₁ = 0.0202, and wR₂ = 0.0529.