Caesium thorium silicate, Cs₂ThSi₆O₁₅

A caesium thorium(IV) silicate has been synthesized serendipitously under high-temperature solid-state conditions by the reaction of Th^IV with a fused silica/alumina reaction crucible. The compound crystallizes in the orthorhombic space group Pca2₁. The crystal structure consists of ThO₆ distorted octa­hedra corner-shared with SiO₄ tetra­hedra to form an anionic three-dimensional framework possessing extended channels containing Cs⁺ cations. Cs₂ThSi₆O₁₅ is a phyllosilicate with the same sheet structure as β-K₃NdSi₆O₁₅.