On basic thallium sulfates: Structure of Tl 2Tl OH(SO 4) 2

The Tl ₂TlOH(SO ₄) ₂ compound is monoclinic, a = 7.758 (3), b = 17.587 (9), c = 7.356 (3) Å, β = 119.91 (3)°, S. G. Cc, Z = 4. The structure was solved by full-matrix least square refinement to R = 0.033 from 1242 single-crystal reflections collected on an automated diffractometer. Tl ⁺ ions ensure bonding between [Tl ^IIIOH(SO ₄) ₂] _∞ sheets. These sheets may be viewed as criss-crossing TlSO ₄ chains. In the [101] direction, the linking of Tl ^III is reinforced by bidentate OH groups, so the usual hexacoordination of trivalent thallium is preserved. A transition occurring at 104°C is under investigation.