Synthesis and crystal structures ofRE7Zn21+xSi2–x[RE= Ce, Pr, and Nd; 0.09 (1)

Abstract

The focus of this paper is on the synthesis and crystal structures of three Zn-rich compounds with the general formulaRE7Zn21+xSi2−x, whereRE= Ce [x= 0.95 (1); heptacerium docosazinc silicon], Pr [x= 0.09 (1); heptapraseodymium henicosazinc disilicon], and Nd [x= 0.53 (1); heptaneodymium docosazinc silicon]. The compounds were obtained by high-temperature reactions, using the respective elements as starting materials. The structures were determined by single-crystal X-ray diffraction. The title compounds crystalize in the orthorhombic space groupPbam(No. 55, Pearson symboloP60) and are isostructural with about a dozenRE7Zn21+xTt2−x(RE= La–Nd;Tt= Ge, Sn, and Pb) compounds previously reported by our group. The results from the present refinements confirm the previously published data onRE7Zn21+xSi2−x(RE= La and Ce;x≃ 1.45) [Maliket al.(2013).Intermetallics,36, 118–126]. Additionally, magnetic susceptibility measurements on the corresponding bulk samples show Curie–Weiss paramagnetic behavior from 5 to 300 K, consistent withRE3+ground states and local-moment magnetism due to the core 4felectrons.