Synthesis and crystal structure of the monoclinic modification of Yb(ReO 4) 3(H 2O) 4

Abstract

Ytterbium(III) tetraaquatris(tetraoxorhenate(VII)), Yb(ReO 4) 3(H 2O) 4, was prepared by the reaction of Yb 2O 3 with concentrated HReO 4 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(H 2O) 4(ReO 4) 2(ReO 4) 2/2] running along [100]. This arrangement shows distorted cubic antiprisms of [Yb(H 2O) 4(ReO 4) 2(ReO 4) 2/2] interconnected via the ReO 4 − 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.