The crystal structure of Sr4PtO6 and two related compounds

The crystal structure of Sr4PtO 6 has been determined by a trial and error method.The crystals are trigonal with space group R3c; the triply primitive hexagonal cell dimensions are a = 9.74, c ----11.90/~.The platinum ions are octahedrally coordinated with oxygen and are linked in the c direction through strontium ions surrounded by trigonal prisms of oxygens.These strings of coordination polyhedra are connected laterally by strontiums in eight fold coordination with oxygen.This structure is of the same type as that reported for K4CdC16.The isolation of one PrO 6 group from the next is postulated as a reason for the ease of hydrolysis of the compound.Sr4IrO G and Sr4RhO 6 have the same structure.