Hydrothermal Synthesis and Structural Investigation of a Crystalline Uranyl Borosilicate

The relevance of multidimensional and porous crystalline materials to nuclear waste reme-diation and storage applications has motivated exploratory research focused on materials discovery of compounds, such as actinide mixed-oxoanion phases, which exhibit rich structural chemistry. The novel phase K1.8 Na1.2 [(UO2)BSi4 O12 ] has been synthesized using hydrothermal methods, rep-resenting the first example of a uranyl borosilicate. The three-dimensional structure crystallizes in the orthorhombic space group Cmce with lattice parameters a = 15.5471(19) Å, b = 14.3403(17) Å, c = 11.7315(15) Å, and V = 2615.5(6) Å3, and is composed of UO6 octahedra linked by [BSi4 O12 ]5− chains to form a [(UO2)BSi4 O12 ]3− framework. The synthesis method, structure, results of Raman, IR, and X-ray absorption spectroscopy, and thermal stability are discussed