Abstract
Two salt-inclusion uranyl silicates, [K3Cs4F] [(UO2)3(Si2O7)2] (compound 1) and [NaRb6F][(UO2)3(Si 2O7)2] (compound 2), have been synthesized at high temperature using mixtures of alkali metal fluorides as fluxes and structurally characterized by single-crystal X-ray diffraction. Both compounds contain UO6 tetragonal bipyramids linked by disilicate groups to form three-dimensional framework structures with identical framework composition but different framework structures and salt inclusions. Both structures contain elliptical 12-ring channels where the K2Cs4F and Rb 6F units are located. They are the first examples of salt-inclusion uranium silicates. The frameworks of 1 and 2 are thermally stable up to 850 and 750 °C, as indicated from powder X-ray diffraction. The 19F and 29Si MAS NMR spectra and the second-harmonic-generation response of 1 are consistent with the crystal structure analysis results. Crystal data: [K3Cs4F][(UO2)3(Si2O 7)2], Cmc21 a = 7.8095(3) A, b = 22.2819(7) Å, c= 14.0861(4) Å, and Z= 4; [NaRb6F][(UO 2)3(Si2O7)2], Pnnm, a=11.1429(2) Å, 0=13.5151(3) Å, c=7.8868(1) Å, and Z=2.
Original language | English |
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Pages (from-to) | 8357-8361 |
Number of pages | 5 |
Journal | Inorganic Chemistry |
Volume | 48 |
Issue number | 17 |
DOIs | |
State | Published - 7 Sep 2009 |