Carbonat-isostere Anionen [SnX3]5− in den Verbindungen Rb6[SnX3]O0,5 und Cs6[SnX3]O0,5 mit X = As,Sb und Bi

Carbonate Isostructural Anions SnX₃]^5? in the Compounds Rb₆SnX₃]O_0.5 and Cs₆SnX₃]O_0.5 with X = As, Sb, and Bi The metallic shining compounds Rb₆SnX₃]O_0.5 and Cs₆SnX₃]O_0.5 with X = As, Sb, and Bi were prepared from the melt starting from adequate mixtures of the elements and SnO₂. They crystallize in the hexagonal system (space group P6₃/mmc, No. 194, Z = 2) with the lattice constants mentioned in ?Inhaltsübersicht”?. In the structures of the isotypic compounds tin and the main group(V) elements build up trigonal planar anions SnX₃]^5? with X = As, Sb, and Bi isostructural to the carbonate anion, oxygen forms isolated O^2? ions. The bond lengths Sn? X are significantly shortened with respect to the sums of Pauling covalent radii. The atoms of the units SnX₃]^5? are coordinated by alkali metal cations forming trigonal prisms and the O^2? anions occupy octahedral holes.