Infinite and Finite Boron Carbon Branched Chains: The Crystal Structures of New Ternary Boride Carbides RE10B7C10 and RE4B3C4*

Abstract

AbstractNew ternary rare earth metal boride carbides RE10B7C10 (RE = Gd, Tb, Dy Ho, Er) and RE4B3C4 (RE = Tb, Dy, Ho, Er, Tm, Yb, Lu) were prepared from the elements by arc‐melting followed by annealing in silica tubes at 1000°C for one month. The crystal structures were investigated by means of single‐crystal X‐ray diffraction data. In the structures of both compounds the boron and carbon atoms form two different types of nonmetal arrangements: one‐dimensional (BC)∞ branched chains and finite CBC units. The branched chains and finite units are differently oriented in both structures. The new ternary rare earth metal boride carbides RE4B3C4 (R = Tb, Dy, Ho, Er, Tm, Yb, Lu) are isotypic to Gd4B3C4, the first characterized member of the rare earth metal borocarbide series in which both one dimentional (BC)∞ branched chains and finite CBC units coexist. Tb10B7C10 is the second characterized member of this family. The compounds RE10B7C10 (RE = Gd, Tb, Dy Ho, Er) are isotypic.