[en] The crystal structure of β-CsReO₄, the room-temperature modification of cesium perrhenate, was determined from single-crystal X-ray data as orthorhombic, space group Pnma, a = 5.7556(9), b = 5.9964(8), c = 14.310(2) A and Z = 4. The structure was refined to R = 0.027, R_w = 0.023 for 779 absorption-corrected reflections. It represents an orthorhombic distortion of the tetragonal high-temperature phase α-CsReO₄. The structure of β-CsReO₄ comprises isolated ReO₄ tetrahedra, linked together by Cs ions. The average Re-O distance was found to be 1.714(4) A. (orig.)