THE FIRST TRIGONAL PLANAR TRANSITION METAL-HYDROGEN COMPLEX IN NABAPDH3

A new quaternary hydride, NaBaPdH3, has been synthesized. The novel st ructure type was refined, in the hexagonal space group P6(3)/mmc, from single-crystal X-ray data complemented by neutron powder diffraction data from the corresponding deuteride. The unit cell dimensions at 150 K were determined to be a = 6.049(1) Angstrom and c = 6.061(3) Angstr om. The structure consists of trigonal planar PdH3 complex anions, wit h formally zerovalent palladium, in a framework of sodium and barium c ounterions. It is related to the CaCuP structure, with the PdH3 unit a t the P atom site and Ba and Na at the Cu and Ca atom sites, respectiv ely.