Neue Suboxid-Cluster [O5Ba18] in den Kristallstrukturen von Ba21M2O5 (M = Si,Ge)

Novel Suboxide Clusters O₅Ba₁₈] in the Crystal Structures of Ba₂₁M₂O₅ (M = Si, Ge) The compounds Ba₂₁M₂O₅ (M = Si, Ge) crystallize in the cubic system with space group Fd3m, lattice constants 2 038.3(10) pm (Si), 2 039.8(9) pm (Ge) resp. and Z = 8. The crystal structure contains isolated Si/Ge atoms coordinated by barium atoms in an icosahedral arrangement. The oxygen atoms are situated in the centers of barium octahedra, four of which share common faces with an additional central octahedron. The novel clusters O₅Ba₁₈] in principal are related to those in the crystal structures of the binary Cs/Rb suboxides.