Solid-state syntheses and single-crystal characterizations of three tetravalent thorium and uranium silicates

Journal Article · Thu Jan 01 04:00:00 EST 2015 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2014.10.018· OSTI ID:1393973

Jin, Geng Bang; Soderholm, L.

Colorless crystals of ThSiO 4 (huttonite) ( 1) and (Ca 0.5Na 0.5) 2NaThSi 8O 20 ( 2) have been synthesized by the solid-state reactions of ThO 2, CaSiO 3, and Na 2WO 4 at 1073 K. Green crystals of (Ca 0.5Na 0.5) 2NaUSi 8O 20 ( 3) have been synthesized by the solid-state reactions of UO 2, CaSiO 3, and Na 2WO 4 at 1003 K. All three compounds have been characterized by single-crystal X-ray diffraction. Compound 1 adopts a monazite-type three-dimensional condensed structure, which is built from edge- and corner-shared ThO 9 polyhedra and SiO 4 tetrahedra. Compounds 2 and 3 are isostructural and they crystallize in a steacyite-type structure. The structure consists of discrete pseudocubic [Si 8O 20] 8- polyanions, which are connected by An4+ cations into a three-dimensional framework. Each An atom coordinates to eight monodentate [Si 8O 20] 8- moieties in a square antiprismatic geometry. Na + and Ca 2+ ions reside in the void within the framework. Raman spectra of 1, 2, and 3 were collected on single crystal samples. 1 displays more complex vibrational bands than thorite. Raman spectra of 2 and 3 are analogous with most of vibrational bands located at almost the same regions. [All rights reserved Elsevier].

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: USDOE Office of Science - Office of Basic Energy Sciences - Chemical Sciences, Geosciences, and Biosciences Division
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1393973
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: C Vol. 221; ISSN 0022-4596
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Raman spectroscopy
silicate
solid-state synthesis
structure
thorium
uranium