Abstract

The new open-framework uranium silicates Na₂(UO₂)(Si₄O₁₀)·2.1H₂O (USH-1) and RbNa(UO₂)(Si₂O₆)·H₂O (USH-3) have been synthesized by hydrothermal reactions at 230 °C. 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.