Rietveld refinement of Y(2)GeO(5).

Y(2)GeO(5) (yttrium germanium penta-oxide) was synthesized by solid-state reaction at 1443 K. The arrangement, which has monoclinic symmetry, is isostructural with Dy(2)GeO(5) and presents two independent sites for the Y atoms. Around these atoms there are distorted six-coordinated YO(6) octa-hedra and seven-coordinated YO(7) penta-gonal bipyramids. The YO(7) polyhedra are linked together, sharing their edges along a surface parallel to ab, forming a sheet. Each of these parallel sheets is inter-connected by means of GeO(4) tetra-hedra, sharing an edge (or vertex) on one side and a vertex (or edge) on the other adjacent side. Parallel sheets of YO(7) polyhedra are also inter-connected by undulating chains of YO(6) octa-hedra along the c axis. These octa-hedra are joined together, sharing a common edge, to form the chain and share edges with the YO(7) polyhedra of the sheets.