Zur Kristallchemie der Oxorhenate

On the Crystal Chemistry of Oxorhenates The review deals with the crystal chemistry of oxorhenates. In contrast to the crystal chemistry of the lately discussed rhodium oxides rhenium shows many and diverse coordination. Examples are square planar polygons, trigonal bipyramids and tetrahedral as well as octahedral surroundings by oxygen. Starting with the oxides ReO₂, Re₂O₇, Re_1,16O₃, Re₃O₁₀ and ReO₃ it will be shown that oxorhenates form isolated tetrahedra, octahedra, Re₂O₁₀‐ and Re₂O₉‐groups. The polyhedra of rhenium are isolated to each other or arranged in one‐dimensional chains, in two dimensional nets and three‐dimensional networks. Rhenium adapts the crystal structures of perowskites, fluorites, pyrochlores, rutiles and stacking variants of the perowskites. Special features are mercuro‐oxorhenates (HgReO₄, Hg₂ReO₅, Hg₅Re₂O₁₀) showing – Hg⁺‐Hg⁺ – groups and Rare Earth‐Oxorhenates (Ln₂ReO₅, Ln₃Re₂O₉, Ln₅Re₂O₁₂) revealing clearly visible Re‐Re – interactions. PbRe₂O₈ and BiReO₄ are remarkable because of one sided open polyhedra, due to the lone pair activity. The positions of lone pairs (e^2? – point charge) are verified by calculations of Madelung parts of lattice energy.