In Situ Hydrogenation and Crystal Chemistry Studies of Co₂Si Type Compounds MgPd₂ and Pd₂Zn

Abstract

The hydrogenation properties of the intermetallic compounds MgPd 2 and Pd 2 Zn, crystallizing in the Co 2 Si type, were studied by in situ thermal analysis (DSC) under hydrogen pressure. Pd 2 Zn does not show any reaction with hydrogen while MgPd 2 reversibly forms the hydride MgPd 2 H. Neutron diffraction on the deuterides reveals the compositions MgPd 2 D 0.861(6) (ambient) and MgPd 2 D 0.97(1) [308(2) K, 2.56(5) MPa deuterium] with hydrogen (deuterium) occupying distorted [MgPd 5 ] octahedral voids. Quantum mechanical calcu-