A Lanthanum-Filled Carbon–Boron Clathrate

Abstract

We report a carbon-boron clathrate with composition 2 La@B6C6 (LaB3C3). Like recently reported SrB3C3,[1] single-crystal X-ray diffraction and computational modelling indicate that the isostructural La member crystallizes in the cubic bipartite sodalite structure (Type-VII clathrate) with La atoms encapsulated within truncated octahedral cages composed of alternating carbon and boron atoms. The covalent nature of the B−C bonding results in a hard, incompressible framework, and owing to the balanced electron count, La3+[B3C3]3− exhibits markedly improved pressure stability and is a semiconductor with an indirect band gap predicted near 1.3 eV. A variety of different guest atoms may potentially be substituted within Type-VII clathrate cages, presenting opportunities for a large family of boron-stabilized, carbon-based clathrates with ranging physical properties.

Publication Title

Angewandte Chemie - International Edition

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