Fluoride crystal structures. Part XVI. Dibromine hexadecafluorotriantimonate(V), [Br2]+[Sb3F16]–

Abstract

Crystals of dibromine hexadecafluorotriantimonate(V) are monoclinic, space group C₂/c, with a unit cell of dimensions a= 13·58, b= 7·71, c= 14·33 Å, β= 93·7°. The structure was refined by three-dimensional least-squares methods, the final R being 0·114 for 609 reflections. In the dibromine cation the two bromine atoms are 2·15 Å apart compared with 2·27 Å in the bromine molecule. The anion has a trans-bridged arrangement at the central antimony atom, with asymmetric fluorine bridges to the outer antimony atoms: Sb(central)–F(bridge) 1·97 Å, Sb(outer)–F(bridge) 2·10 Å.