The crystal structure of β-Thallium perrhenate

β-TlReO₄, the room temperature modification of thallium perrhenate, has been investigated by means of single crystal X-ray diffraction. It crystallizes in the monoclinic space group P112₁/a with a = 5.636(1), b = 17.428(3), c = 13.353(3) Å, γ = 89.86(2)° and Z = 12. The structure has been refined to R = 0.063 (wR = 0.053) using 2 020 absorption-corrected reflections. The title compound can be described as an intergrowth of β-CsReO₄ and scheelite type blocks at unit cell level. The structure of β-TlReO₄ consists of isolated ReO₄ tetrahedra linked together by TlO₈ and TlO₉ polyhedra. Based upon group theoretical considerations the structural relationships between β-TlReO₄, β-CsReO₄, α-CsReO₄ and scheelite type are discussed.