The reversible hydrogenation of BiPd3 followed by in situ methods and the crystal structure of PbPd3D0.13(1)

• Published in: Journal of alloys and compounds 2018-01, Vol.731, p.1001-1008
• Main Authors: Götze, A., Hansen, T.C., Kohlmann, H.
• Format: Article
• Language: English
• Subjects: Hydrogen; In situ techniques; Intermetallics; Metal hydrides; Neutron diffraction; Palladium
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.10.107

The hydrogenation properties of binary palladium-rich intermetallic compounds MPd3 (M = Pb, Bi) were studied by X-ray powder diffraction and by in situ thermal analysis (DSC) under hydrogen pressure. Ex situ neutron powder diffraction reveals deuterium filled [Pd6] octahedral voids in a cubic anti-perovskite type structure for PbPd3D0.13(1) (Pm3¯m, a = 404.033(6) pm, deuterium occupation = 0.13(1)) and in a ZrAl3 type for BiPd3D0.19(1) and BiPd3D0.23(1) (I4/mmm, a = 404.72(1) pm, c = 1662.64(6) pm, z(Bi) = 0.1320(1), z(Pd3) = 0.3797(2), deuterium occupation = 0.46(1)). In situ neutron diffraction (using deuterium) reveals full reversibility of the hydrogenation and dehydrogenation reaction for BiPd3 without intermediate phases and variable hydrogen content in the hydride. The relation of the crystal structures of BiPd3 (akin to double-hexagonal close packing) and its hydride with filled ZrAl3 type (ordered superstructure of cubic close packing) is discussed in view of a possible reaction mechanism. •BiPd3 takes up hydrogen and forms a hydride BiPd3H≤0.23(1) with hydrogen in octahedral [Pd6] voids.•Hydrogenation changes the close packing from double hexagonal to cubic.•Hydride formation was followed by in situ methods (thermal analysis and neutron diffraction).•PbPd3 retains its AuCu3 type to form PbPd3H0.13(1) with hydrogen in octahedral [Pd6] voids.