The rare earth metal hydride tellurides REHTe (RE=Y, La–Nd, Gd–Er)

Abstract

Abstract The synthesis and crystal structure of a series of rare earth metal hydride tellurides with the composition RE HTe ( RE = Y, La–Nd, Gd–Er) is reported. These compounds have been obtained by the reaction of rare earth metal dihydrides ( RE H 2 ) with elemental tellurium in sealed tantalum capsules at T = 700°C using cesium chloride (CsCl) as fluxing agent, which can be washed away with water due to the astonishing insensitivity of these hydride tellurides ( RE HTe) against hydrolysis. All of the compounds crystallize in the hexagonal space group P 6̅ m 2 with a filled WC-type crystal structure, exhibiting a mutual trigonal-prismatic coordination of the heavy ions ( RE 3+ and Te 2− ), while the hydride anions reside in the trigonal prismatic voids surrounded by three rare earth metal cations expanding their coordination pattern to a tricapped trigonal prism. This 1H-type crystal structure is compared with the 1H- and 2H-type structures of the respective hydride selenides ( RE HSe, RE = Y, La–Nd, Gd–Tm, Lu). Both hexagonal basic crystal structures can be derived from the AlB 2 -type structure as demonstrated in a Bärnighausen tree by group-subgroup relationships.