Hydrogen-induced structural and valence change in CeIrAl - art. no. 172418

The compound CeIrAl crystallizes in the orthorhombic epsilon -TiNiSi-type s tructure in which the cerium ions are in a mixed-valent state as inferred f rom its weakly temperature dependent magnetic susceptibility. This compound absorbs hydrogen at ambient temperature to form CeIrAlH2. A structural tra nsformation from orthorhombic to hexagonal structure takes place on hydroge n absorption. Further, the magnetic susceptibility of the hydride exhibits Curie-Weiss behavior, typical of local moment on Ce3+ ions. Thus hydrogen a bsorption brings about dramatic changes in the structure and the valence st ate of cerium in CeIrAl.