Thermal effects in the structure of potassium perrhenate

The structure of KReO 4 has been determined by neutron powder diffraction at 298, 150 and 15 K. The structural parameters at room temperature are consistent with the results of Lock & Turner (Acta Cryst. (1975), B31, 1764-1765] and their temperature dependences are normal. The orientation of the anion changes by 1.20 (13) o over this temperature range