A new simple criterion for distinguishing the types of structures in eight-coordinate complexes: The pattern of bond angles

Abstract

Square antiprismatic, triangular dodecahedral and (rectangularly) bicapped trigonal prismatic (or hendecahedral) eight-coordinate structures are shown to manifest distinct patterns of LML′ bond angles, which are validated by many straightforward examples from the literature. Our criterion was used to re-classify seven published structures: in one of these, a completely new type of eight-coordination, christened the C s decahedron, has been discovered. The same type of analysis has been applied to the rarer types of eight-coordination: the cube, the hexagonal bipyramid, the axially bicapped trigonal antiprism and the trigonally bicapped octahedron, and the axially bicapped trigonal prism: useful insights have thus been obtained concerning several published structures.