Energy characteristics of fluouranates (IV) of alkali metals

Spectroscopic studies and crystal-field analysis of U3+ ions in RbY2Cl7 single crystals

“…8 They reindexed the x-ray powder pattern on the basis of RbU 2 Cl 7 being isostructural with RbDy 2 Cl 7 and RbY 2 Cl 7 . 11 This result has been confirmed. 10 Each 5 f 3 →5 f 3 absorption band of the U 3ϩ ion in RbY 2 Cl 7 consists of two components, which arise from the different crystal fields of the two intrinsic sites of approximately C 2v point symmetry.…”

“…9 Recently, another preparative method along with structural, magnetic, optical absorption, and Raman characterization of the compound has been reported. 10 Volkov et al 11 had revised the earlier crystal structure analysis for RbU 2 Cl 7 12 on the basis of the single crystal data for RbDy 2 Cl 7 reported by Meyer. 8 They reindexed the x-ray powder pattern on the basis of RbU 2 Cl 7 being isostructural with RbDy 2 Cl 7 and RbY 2 Cl 7 .…”

Examination of the short-range structure of molten salts: ThF4, UF4, and related alkali actinide fluoride systems

“…Like for the other AF-AnF 4 systems, the CN distribution is calculated to be in the 6-10 range, with a small contribution from CN = 9 and a negligible one from CN = 10. The atomic environment for the An 4+ cations in the crystal phases occurring in the CsF-AnF 4 binary systems is mostly a tricapped trigonal prism (CN = 9) 38 except for an octa-coordinated site in Cs 2 UF 6 (space group Cmcm, 39 ) and an exceptionally rare 1coordinated site in one of the polymorphs of CsThF 5 (space group P4/nmm 40 ). Hence, as discussed earlier for thorium and uranium tetrafluorides, thermal disorder reduces the coordination number in the first solvation shell, as CN = 6 becomes more prevalent than in melts based on other alkali fluorides.…”

Luminescence and Excitation Spectra of U3+doped RbY2Cl7Single Crystals

“…[1]. X-ray structural investigations [1][2][3][4] show that the compound crystallizes in the orthorhombic system, space group Pnma (D2h) and is isotypic with RbY2 Cl 7 and RbU2Cl7. The central metal ions occupy two distinct positions of the same m(Cs ) symmetry.…”