palladiumhydrider

Palladium hydrider, more commonly called palladium hydride, is a class of compounds in which hydrogen is associated with palladium. The term can refer to solid-state hydrides formed when palladium metal absorbs hydrogen, as well as to discrete hydrido complexes of palladium in organometallic chemistry.

In solid palladium hydride, hydrogen is dissolved in the palladium lattice, producing PdHx with x varying by temperature and hydrogen pressure. The palladium lattice is face-centered cubic; hydrogen occupies interstitial sites, causing lattice expansion and a change in physical properties. The system typically exhibits two observed regimes, known as the α-phase (low hydrogen content) and the β-phase (high hydrogen content). The hydride formation is reversible and palladium can absorb and desorb hydrogen many cycles.

In catalysis and materials chemistry, palladium hydride species are important as intermediates in hydrogenation and hydrofunctionalization reactions. On the metal surface, H2 dissociation generates surface hydride species that participate in hydrogen transfer steps. In homogeneous catalysis, a variety of palladium hydrido complexes with phosphine or N-heterocyclic carbene ligands are known and used as reactive intermediates.

Safety and handling: hydrogen gas is flammable and requires appropriate controls; solid palladium hydride is relatively stable but must be treated as a hazardous material under high hydrogen pressure, and proper equipment should be used when handling hydrogen-containing palladium materials.