Zur kristallchemie der oxoruthenate

Abstract

The review gives systematic of crystal structures of oxoruthenates. Ruthenium shows mainly octahedral surrounding of ruthenium by oxygen besides RuO4-tetrahedra, square RuO5-pyramids, trigonal RuO 5-bipyramids and planar RuO4-polygons in a few cases. A grade in scale of arrangement of RuO6-octahedra is the linking from to each other isolated RuO6-octahedra, condensed octahedra of the type Ru2O9 and Ru3O12, followed by ∞1[RuO3]-, ∞1[RuO4]- and ∞1[RuO 5]-chains, ring structures, in plane as well as waved nets up to tunnel structures and 3-dimensional octahedra networks. A great part of the review deals with the stacking of MO6-octahedra, (Ru 2O9)-octahedra-double, (Ru3O 12)-octahedra-triple, variants of perowskites in the broadest sense and variants of the K2NiF4-type (Ruddlesden-Popper phases). Finally there exist two cluster compounds (Al0.68RuSn 6O8; Sn15Ru3O14), showing no oxygen surrounding of ruthenium. In the presented oxoruthenates ruthenium shows a broad spectrum of oxidation states ranging from Ru3+ up to Ru7+. In some compounds ruthenium occupies only one point position. In combination with elements of unambiguous valence states the oxidation number shows broken values like Ru4,5+; Ru5,33+ or Ru 5,75+. Other examples show ruthenium at different point positions and mixed valences too. In these cases calculations of partial Coulomb-Terms of lattice energy are consulted in order to decide between different oxidation states of ruthenium. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.