The crystal chemistry of four thorium sulfates

Four thorium sulfate compounds have been synthesized and characterized. [Th(SO4)2(H2O)7]·2H2O (ThS1) crystallizes in space group P21/m, a=7.2488(4), b=12.1798(7), c=8.0625(5) Å, β=98.245(1)o; Na10[Th2(SO4)9(H2O)2]·3H2O (ThS2), Pna21, a=17.842(2), b=6.9317(8), c=27.550(3) Å; Na2[Th2(SO4)5(H2O)3]·H2O (ThS3), C2/c, a=16.639(2), b=9.081(1), c=25.078(3) Å, β= 95.322(2)o; [Th4(SO4)7(OH)2(H2O)6]·2H2O (ThS4), Pnma, a=18.2127(9), b=11.1669(5), c=14.4705(7) Å. In all cases the Th cations are coordinated by nine O atoms corresponding to SO4 tetrahedra, OH groups, and H2O groups. The structural unit of ThS1 is an isolated cluster consisting of a single Th polyhedron with two monodentate SO4 tetrahedra and seven H2O groups. A double-wide Th sulfate chain is the basis of ThS2. The structures of ThS3 and ThS4 are frameworks of Th polyhedra and sulfate tetrahedra, and each contains channels that extend through the framework. One of the Th cations in ThS3 is coordinated by a bidentate SO4 tetrahedron, and ThS4 is unusual in the presence of a pair of Th cations that share a polyhedral face.

The structures of four hydrous thorium sulfates are reported that have structural units consisting of finite clusters, chains, and frameworks.Figure optionsDownload as PowerPoint slideHighlights
► Four hydrous thorium sulfates have structural units consisting of finite clusters, chains, and frameworks.
► In each the Th cations are coordinated by nine O atoms from SO4 tetrahedra, OH groups, and H2O groups.
► The details of the linkages of ThO9 polyhedra and sulfate tetrahedra vary considerably in these structures.