The novel open-framework uranium silicates Na2(UO2)(Si4O10)•2.1H2O (USH-1) and RbNa(UO2)(Si2O6)•H2O (USH-3)

The new open-framework uranium silicates Na-2(UO2)(Si4O10).2.1H(2)O (USH-1) and RbNa(UO2)(Si2O6).H2O (USH-3) have been synthesized by hydrothermal reactions at 230 degreesC. USH-1 has a framework structure formed from silicate single layers cross-linked by interlayer UO6 tetragonal bipyramids. The silicate layers consist of interconnected tetrahedral 4-rings and 8-ring voids. The 8-ring voids are lined up to form 1-dimensional channel systems in the framework. In contrast to the silicate layers of USH-1, individual 4-rings of silicate tetrahedra are found in USH-3 which are cross-linked by UO6 tetragonal bipyramids to form an open framework.