title: Hydrogenation-induced insulating state in the intermetallic compound LaMg2Ni.
abstract: Hydrogenation-induced metal-semiconductor transitions usually occur in simple systems based on rare earths and/or magnesium, accompanied by major reconstructions of the metal host (atom shifts >2 A). We report on the first such transition in a quaternary system based on a transition element. Metallic LaMg2Ni absorbs hydrogen near ambient conditions, forming the nonmetallic hydride LaMg2NiH7 which has a nearly unchanged metal host structure (atom shifts <0.7 A). The transition is induced by a charge transfer of conduction electrons into tetrahedral [NiH4]4- complexes having closed-shell electron configurations.
authors.affiliation: Laboratory of Crystallography, University of Geneva, 1211 Geneva 4, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Yvon
authors.forename: G
authors.initials: G
authors.lastname: Renaudin
authors.forename: C M
authors.initials: CM
authors.lastname: Wei
authors.forename: M Y
authors.initials: MY
authors.lastname: Chou