Synthesis and crystal structures of Cs MgD and Cs MgD 2 4 3 5

The title compounds were prepared by sintering stoichiometric mixtures of the binary deuterides in an autoclave under 65 bar pressure at 625 K. Neutron powder diffraction reveals a b-K SO type structure for Cs MgD (space group Pnma, a58.5988(4), b56.6234(3), 2 4 2 4 ˚ ˚ c511.5988(5) A) and a Cs CoCl type structure for Cs MgD (space group I4/mcm, a58.4022(2), c512.6951(4) A). In both deuterides 3 5 3 5 ˚ ˚ magnesium is tetrahedrally coordinated by deuterium. The Mg–D bond distances (1.82–1.88 A in Cs MgD and 1.84 A in Cs MgD) are 2 4 3 5 ˚ longer by 0.02 A, on the average, than those in the corresponding rubidium analogues. 1. Introduction for 5 days. The reaction products obtained were of white colour. They were pyrophoric and extremely sensitive to Magnesium is a useful constituent for hydrogen storage air and moisture. The binary deuterides were prepared by materials [1,2]. In combination with alkali metals such as deuteration of metallic caesium (STREM 99.9%) and rubidium it forms a series of saline metal hydrides such as