Preparation, Crystal Structures, and Properties of Rhenates with Multiple Re–Re Bonds: Ln2ReO5 (Ln=Sm, Eu, Gd), Ln3Re2O9 (Ln=Pr, Nd, Sm), and Ln4Re6O19 (Ln=La–Nd)

摘要: Most of the title compounds were prepared by reaction rare-earth metaperrhenates Ln(ReO4)3 with metals in sealed silica tubes. Nd4Re6O19 was obtained intermetallic compound NdRe2 metaperrhenate Nd(ReO4)3. The Ln2ReO5 crystallize a tetragonal structure (P4/n, Z=4), which determined from four-circle X-ray diffractometer data twinned crystals Eu2ReO5 [a=861.0(4) pm, c=574.3(3) pm] and refined for Gd2ReO5 [a=858.8(4) c=569.6(2) pm]. Ln3Re2O9 are isotypic La3Re2O9, however, somewhat differing oxygen coordination atoms, as shown refinement single-crystal Sm3Re2O9 [P1, a=551.8(1) b=678.8(2) c=1086.7(3) α=76.57(1)°, β=75.56(2)°, γ=68.66(1)°]. rhenates Ln4Re6O19 have first La4Re6O19. rhenium atoms Ln2ReO5, oxidation number +4, paired formal Re–Re triple bond (225 pm) square-antiprismatic (Re2O8). In two kinds Re2 pairs present. Re(IV) again distance 225 pm. They situated prism atoms. other +5, octahedral coordination. form via common edge their octahedra double 242 magnetic properties these indicate that do not carry any substantial moments. crystal structures reduced oxorhenates elements briefly reviewed. lengths correlate order deduced states.