HIGH-PRESSURE SYNTHESIS AND STRUCTURE OF RB2PTH6 AND CS2PTH6, TERNARYHYDRIDES WITH K2PTCL6-STRUCTURE

The ternary platinum hydrides Rb2PtH6 and Cs2PtH6 were synthesized by the reaction of rubidium hydride and cesium hydride, respectively, wit h platinum sponge under a hydrogen pressure above 1500 bar at 500 degr ees C. X-ray investigations on powdered samples and elastic neutron di ffraction experiments on the deuterated compounds at the time-of-fligh t spectrometer POLARIS led to their complete structure determination. Their atomic arrangements are isotypic with that of K2PtCl6 containing isolated [PtH6](2-)-octahedra (space group: Fm (3) over bar m, Z = 4) .