Sequestration and Storage of Uranium atom using polyoxotungstates: Synthesis of polytungstodioxouranate(V I)

The knowledge of uranium and its waste products behavior in environment is of great concern for many scientists ill several different research fields. The high thermal stability and radiation-resistant natures of polyoxometalates in particular, attract attention to use of these species for the separation and sequestration of radioactive wastes. Reaction of [XW9O33, 34]n- anions with lanthanide and actinide cations which demand coordination numbers greater than six, yields a variety of polyoxoanions with unanticipated stoichiometries and structures [3, 4]. We report the syntheses of the first uranyl-containing polyrungstates with As(III) as the hetero atom that is formed by the reaction of a neutralized (p H 7-7.5) solution of WO42-and As2O3 with an UO22+ solution in a stoichiometric ratio. We have synthesized the sodium salt [As2W18U2O70]14 and characterized by elemental analysis, IR, UV spectroscopies and elemental analysis. The sodium salt contain two UO22+ sandwiched between two [AsW9O33]9- groups. The formation of this complex suggests the possibility of thermal conversion to uranium-rich tungsten bronzes for radioactive waste storage