High-temperature, high-pressure hydrothermal synthesis, characterization, and structural relationships of mixed-alkali metals uranyl silicates

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/101811

Title:	High-temperature, high-pressure hydrothermal synthesis, characterization, and structural relationships of mixed-alkali metals uranyl silicates
Authors:	李光華;Chen, Yi-Hsin;Liu, Hsin-Kuan;Chang, Wen-Jung;Tzou, Der-Lii;Lii, Kwang-Hwa
Contributors:	理學院化學學系
Keywords:	ALKALI METALS;ANIONS;CATIONS;Chains;Channels;Crystal structure;Hydrothermal;HYDROTHERMAL SYNTHESIS;INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY;LAYERS;MOLECULES;MONOCLINIC LATTICES;MONOCRYSTALS;PHOTOLUMINESCENCE;Silicates;Silicon;THERMAL GRAVIMETRIC ANALYSIS;Thermogravimetric analysis;Three dimensional;URANIUM DIOXIDE;Uranium silicate;URANIUM SILICATES;URANYL SILICATES;WATER;X RADIATION;X-RAY DIFFRACTION
Date:	2016-04-01
Issue Date:	2026-04-21 14:46:16 (UTC+8)
Publisher:	Academic Press Inc.;United States: Elsevier Inc
Abstract:	摘要： Three mixed-alkali metals uranyl silicates, Na3K3[(UO2)3(Si2O7)2]·2H2O (1), Na3Rb3[(UO2)3(Si2O7)2] (2), and Na6Rb4[(UO2)4Si12O33] (3), have been synthesized by high-temperature, high-pressure hydrothermal reactions at 550°C and 1440bar, and characterized by single-crystal X-ray diffraction, photoluminescence, and thermogravimetric analysis. Compound 1 and 2 are isostructural and contain layers of uranyl disilicate. The smaller cation, Na+, is located in the intralayer channels, whereas the larger cations, K+ and Rb+, and water molecule are located in the interlayer region. The absence of lattice water in 2 can be understood according to the valence-matching principle. The structure is related to that of a previously reported mixed-valence uranium(V,VI) silicate. Compound 3 adopts a 3D framework structure and contains a unique unbranched dreier fourfold silicate chain with the structural formula {uB,41∞}[3Si12O33] formed of Q2, Q3, and Q4 Si. The connectivity of the Si atoms in the Si12O3318− anion can be interpreted on the basis of Zintl–Klemm concept. Crystal data for compound 1: triclinic, P-1, a=5.7981(2) Å, b=7.5875(3) Å, c=12.8068(5) Å, α=103.593(2)°, β=102.879(2)°, γ=90.064(2)°, V=533.00(3)Å3, Z=1, R1=0.0278; compound 2: triclinic, P-1, a=5.7993(3) Å, b=7.5745(3) Å, c=12.9369(6) Å, α=78.265(2)°, β=79.137(2)°, γ=89.936(2)°, V=546.02(4) Å3, Z=1, R1=0.0287; compound 3: monoclinic, C2/m, a=23.748(1) Å, b=7.3301(3) Å, c=15.2556(7) Å, β=129.116(2)°, V=2060.4(2) Å3, Z=2, R1=0.0304. Three mixed-alkali metals uranyl silicates were synthesized under hydrothermal conditions at 550°C and 1400bar and structurally characterized by single-crystal X-ray diffraction. Two of them have a layer structure with the alkali metal cations within and between the layers. The third one adopts a 3D framework structure and contains a unique unbranched dreier fourfold silicate chain formed of Q2, Q3, and Q4 Si. [Display omitted] •Three new mixed-alkali metals uranyl silicates were synthesized by high-T, high-P hydrothermal method and structurally.•Two compounds adopt a layer structure and the third one has a 3D framework structure.•The 3D framework structure contains a unique unbranched dreier fourfold silicate chain formed of Q2, Q3, and Q4 Si. 出版者： United States: Elsevier Inc 出版日期： 2016-04-01 出處： Journal of solid state chemistry, 2016-04, Vol.236, p.55-60 版權： 2015 Elsevier Inc. 識別號： ISSN: 0022-4596 識別號： EISSN: 1095-726X 識別號： DOI: 10.1016/j.jssc.2015.07.034
Appears in Collections:	[Department of Chemistry] journal & Dissertation

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