Structural investigation and hydrogen storage capacity of LaMg2Ni9 and (La0.65Ca0.35)(Mg1.32Ca0.68)Ni9 of the AB2C9 type structure

Abstract A new quaternary magnesium based alloy (La 0.65 Ca 0.35 )(Mg 1.32 Ca 0.68 )Ni 9 and its hydride have been synthesized and their crystal structures were determined by Guinier–Hagg X-ray powder diffraction. The compound has a hexagonal structure and is isostructural with LaMg 2 Ni 9 (AB 2 C 9 type), in which Ca partially occupies both A and B sites. The hydrogen absorption/desorption properties were determined by pressure–composition isotherms and compared with LaMg 2 Ni 9 . (La 0.65 Ca 0.35 )(Mg 1.32 Ca 0.68 )Ni 9 absorbs ∼1.87 wt.% H 2 at ∼3.3 MPa H 2 and 283 K.