Fluoride crystal structures. Part XXI. Trifluorotellurium(IV)µ-fluorobis[pentafluoroantimonate(V)

Abstract

The interaction of tellurium tetrafluoride and antimony pentafluoride gives the title compound as a minor product. Crystals are monoclinic, space group P21/c, a= 7·48 ± 0·01, b= 14·29 ± 0·02, c= 9·72 ± 0·01 A, β= 91·0°± 0·2°. The structure was solved by Patterson and Fourier methods and refined by three-dimensional least-squares methods to R 0·095 for 824 reflections measured photographically. Although the atomic arrangement is consistent with the ionic formulation [TeF3]+[Sb2F11]– there is considerable interaction between the ions through fluorine bridging. The cation has C3v symmetry, with a mean Te–F distance of 1·84 A, and there are three long contacts of 2·54, 2·55, and 2·69 A to bridging fluorine atoms to give a much distorted octahedral co-ordination for tellurium, very similar to that found for selenium in [SeF3]+[Nb2F11]–.