NEW DEVELOPMENTS IN URANIUM-OXIDE CRYSTAL CHEMISTRY: MINERALS AS INSPIRATION FOR NOVEL SOLID-STATE COMPOUNDS

Several new uranyl (UO₂²⁺ containing) compounds have been synthesized based on inspiration from structural themes found in uranium oxide minerals. The novel uranyl molybdate, (C₂H₃N₃)UO₂Mo₂O₇, is found to have a sheet structure identical to that of iriginite [(UO₂)Mo₂O₇(H₂O)₂](H₂O), yet differs in its interlayer composition as a result of replacing bound H₂O molecules with a coordinated organic structure directing agent, 1,2,4-triazole (C₂H₃N₃). Further, controlled oxidization of such organic species under hydrothermal conditions has been shown to influence uranium valency in Zn_0.5[(U⁵⁺)_2-x(U⁶⁺)_x(UO₂)₄(OH)₂(H₂O)_4-x(O_8+x)]·3.2H₂O. This material is a rare example of a U(V) compound and has a sheet structure related to that found in wyartite (CaU⁵⁺(UO₂)₂(CO₃)O₄(OH)(H₂O)₇). Lastly, several new metal-organic-frameworks (MOFs) have been synthesized by tethering [(UO₂)O₆] hexagonal bipyramids, the fundamental building blocks of uranyl carbonate minerals, through dibasic carboxylic acids.

Presentation Time: 10:45 AM-11:00 AM
NEW DEVELOPMENTS IN URANIUM-OXIDE CRYSTAL CHEMISTRY: MINERALS AS INSPIRATION FOR NOVEL SOLID-STATE COMPOUNDS
CAHILL, Christopher L., BORKOWSKI, Lauren A., and DANEK, Jacquelynn, Department of Chemistry, George Washington Univ, 725 21st Street, NW, Washington, DC 20052, cahill@gwu.edu Several new uranyl (UO₂²⁺ containing) compounds have been synthesized based on inspiration from structural themes found in uranium oxide minerals. The novel uranyl molybdate, (C₂H₃N₃)UO₂Mo₂O₇, is found to have a sheet structure identical to that of iriginite [(UO₂)Mo₂O₇(H₂O)₂](H₂O), yet differs in its interlayer composition as a result of replacing bound H₂O molecules with a coordinated organic structure directing agent, 1,2,4-triazole (C₂H₃N₃). Further, controlled oxidization of such organic species under hydrothermal conditions has been shown to influence uranium valency in Zn_0.5[(U⁵⁺)_2-x(U⁶⁺)_x(UO₂)₄(OH)₂(H₂O)_4-x(O_8+x)]·3.2H₂O. This material is a rare example of a U(V) compound and has a sheet structure related to that found in wyartite (CaU⁵⁺(UO₂)₂(CO₃)O₄(OH)(H₂O)₇). Lastly, several new metal-organic-frameworks (MOFs) have been synthesized by tethering [(UO₂)O₆] hexagonal bipyramids, the fundamental building blocks of uranyl carbonate minerals, through dibasic carboxylic acids.
2003 Seattle Annual Meeting (November 2–5, 2003)

Session No. 212 The Impact of Crystal Chemistry in the Earth Sciences II: A Tribute to Charles T. Prewitt, Recipient of the 2003 Roebling Medal of the Mineralogical Society of America Washington State Convention and Trade Center: Ballroom 6A 8:00 AM-12:00 PM, Wednesday, November 5, 2003 Geological Society of America Abstracts with Programs, Vol. 35, No. 6, September 2003, p. 536
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2003 Seattle Annual Meeting (November 2–5, 2003)
Paper No. 212-11