The anti-perovskite type hydride InPd3H0.89

Hydrogenation of tetragonal InPd3 in the ZrAl3 type structure (four-fold ccp superstructure) yields a hydride with a cubic AuCu3 type structure (one-fold ccp superstructure). Deuterium can be located by neutron powder diffraction in octahedral voids surrounded exclusively by palladium, [Pd6], which are 88.5(6)% occupied in a statistical manner. The resulting deuteride InPd3D0.89 thus crystallizes in a cubic anti-perovskite type structure (space group Pm3¯m (no. 221), a=402.25(1) pm at 299(2) K). The Pd–D distance of 201.13(1) pm is typical for interstitial hydrides with palladium. Inelastic neutron scattering on the hydride InPd3H0.89, which shows a spectrum similar to that of binary palladium hydride, confirms the cubic site symmetry of hydrogen in [Pd6] interstices. This is also confirmed by the absence of any quadrupole splitting in the 2D-NMR signal of the deuteride. 1H NMR spectra of InPd3H0.89 do not show any motional narrowing. Values found for the H jump rate τ−1 in InPd3H0.89 remain below 106 s−1 in the studied temperature range 28–360 K, indicating a small hydrogen mobility in InPd3H0.8 as compared with binary palladium hydride, PdH≤1. This can be attributed to the large spatial separation of the [Pd6] sites.

Hydrogen induces a rearrangement in InPd3 from a ZrAl3 type structure to a cubic AuCu3 type structure, thus forming an anti-perovskite type hydride InPd3H0.89.Figure optionsDownload as PowerPoint slide