The crystal structure of β‐Thallium perrhenate

β‐TlReO 4 , 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 P112 1 /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‐CsReO 4 and scheelite type blocks at unit cell level. The structure of β‐TlReO 4 consists of isolated ReO 4 tetrahedra linked together by TlO 8 and TlO 9 polyhedra. Based upon group theoretical considerations the structural relationships between β‐TlReO 4 , β‐CsReO 4 , α‐CsReO 4 and scheelite type are discussed.