HIGH-PRESSURE SYNTHESIS AND STRUCTURE OF NA2PTH6

The ternary sodium platinum hydride Na2PtH6 was prepared via the react ion of sodium hydride with platinum sponge at 770 K and 1500-1800 bar hydrogen pressure. Its structure was determined by X-ray investigation s of powdered samples in the temperature range 295-9 K and a neutron d iffraction experiment on the deuterated compound at room temperature. The atomic arrangement in Na2PtH6 is isotypic with that of K2PtCl6. Th ese results show that platinum could be oxidized under high hydrogen p ressure up to oxidation state 4+.