An Open-Framework Thorium Sulfate Hydrate with 11.5 Å Voids

We report the synthesis of a thorium sulfate hydrate with 11.5 angstrom open channels that propagate through the structure. The compound crystallizes in the tetragonal space group P4(2)/nmc, a = b = 25.890(4) angstrom, c = 9.080(2) angstrom, Z = 8, V = 6086.3(2) angstrom(3). The thermal stability of the compound was investigated using thermogravimetric analysis and high-energy X-ray scattering (HEXS) revealing that the compound begins to undergo decomposition near 200 degrees C with an accompanied loss in crystallinity. The immediate coordination environment about the thorium atoms remains intact through heating to 500 degrees C as demonstrated by HEXS, Further heating reveals the formation of at least two crystalline phases, Th(SO4)(2) and ThO2, which ultimately decompose to ThO2.