EXISTENCE OF LINEAR PTH2(2-) AND PLANAR PDH4(2-) ANIONS IN MIXED-CRYSTALS OF THE SYSTEM NA2PDH2-NA2PTH4

We report experiments on the mutual exchange of platinum and palladium in the ternary hybrides Na2PdH2 and Na2PtH4. The first compound contains linear PdH2(2-) units, the latter planar PtH4(2-) units. X-ray investigations of the reaction products show that the noble metal in each hydride can partially be replaced by that of the other. The resulting molar volumes suggest that the hydride coordination of the host lattice is adopted. Hence, the PtH2(2-) anions are stabilized in the host structure of Na2PdH2 as well as the PdH4(2-) anions in that of Na2PtH4.