[en] Ytterbium(III) tetraaquatris(tetraoxorhenate(VII)), Yb(ReO₄)₃(H₂O) 4, was prepared by the reaction of Yb₂O₃ with concentrated HReO₄ at room temperature. The colorless compound crystallizes in the monoclinic space group P2 1/n (No. 14) with four formula units per unit cell (a=730.5(1) pm, b=1484.1(5) pm, c=1311.7(2) pm, β=93.69(1)). The main feature of the crystal structure is the formation of chains ∞¹[Yb(H₂O)₄(ReO₄)₂(ReO₄)₂ / 2] running along [100]. This arrangement shows distorted cubic antiprisms of [Yb(H₂O)₄(ReO₄) 2(ReO₄)₂ / 2] interconnected via the ReO₄^- ligands. The chains are held together in the solid by hydrogen bonding. The compound is paramagnetic and follows the Curie-Weiss law with a magnetic moment of 4.0 μ B at room temperature and θ=-42 K. It loses hydration water in two steps at temperatures below 400 K; decomposition begins at 850 K, forming Yb 2O 3(Re 2O 7) 2 and is complete at 1350 K leading to Yb 2O 3 as final product