From molecular Sb units to infinite chains, layers, and networks: Sb-Sb interactions in metal-rich antimonides

A multitude of metal-rich pnictides and chalcogenides of the valence-electr on-poor transition elements M have been uncovered in recent years. Common s tructural features of all these compounds are extended metal atom substruct ures (of different kinds) and the occurrence of metal-pnicogen and metal-ch alcogen bonds, respectively. Bonding homonuclear interactions between the m ain-group elements E are found only in the structures of the antimonides an d bismuthides. This bonding situation is associated with highly complex cry stal structures in the latter cases, because of the presence of three diffe rent types of bonding, i.e. M-E, M-M and E-E bonds.