Unusual crown ether encapsulation of a chloroscandium(III) cation. Structure of threaded [ScCl2(18-crown-6)][SbCl6]

Abstract

Halide abstraction from ScCl₃ using SbCl₅ provides the ScCl₂⁺ cation, which is stabilised by crown ether complexation to give the ionic complex [ScCl₂(18-crown-6)][SbCl₆]; the cation has a threaded structure in which the scandium is seven-coordinate (approximately pentagonal bipyramidal) and the crown adopts an unsymmetrical conformation leaving one oxygen site uncoordinated to the central metal.