Structure of anhydrous titanyl sulfate, titanyl sulfate monohydrate and prediction of a new structure

(1) Titanyl sulfate, TiOSO4, Mr=159.96, orthorhombic, P21ma, a=10.942(1), b=5.158(1), c=25.726(2) A, U=1452.0(3) A3, Dm(flotation)=2.96(2), Dx=2.93(1) g cm-3, Z=16, λ(Mo Kα)=0.7107 A, μ=23.46 cm-1, F(000)=1248, T=293 K, final R=0.168 for 2333 counter reflections. A combined X-ray and transmission electron microscopy study allowed the determination and refinement of this structure on a supercell of WPO5 (a and b equal those above but c is 4xc). The structure consists of an infinite array of corner-shared octahedra and tetrahedra and Ti-O distances range from 1.70(2) to 2.05(1) A. (2) Titanyl sulfate monohydrate, TiOSO4.H2O, Mr=177.97, orthorhombic, P212121, a=9.818(1), b=5.133(1), c=8.614(2) A, U=434.1(2) A3, Z=4, Dm(flotation)=2.71(1), Dx=2.72(1) g cm-3, λ(Mo Kα)=0.7107 A, μ=23.46 cm-1, F(000)=352, T=293 K, final R=0.0190 for 1985 counter reflections. The structure consists of [TiO]n2n+ chains parallel to the crystallographic b axis linked by sulfate tetrahedra to form the three-dimensional structure. The titanyl bridge is asymmetric [1.6870(9) and 1.9641(8) A] and Ti-O distances range from 1.687 to 2.136 A. A new structure derived from that of titanyl sulfate hydrate is predicted. (orig.)