Fluoride crystal structures. Part X. Trifluoroselenium(IV)µ-fluorobis[pentafluoroniobate(V)]

Abstract

The interaction of selenium tetrafluoride and niobium pentafluoride at room temperature produces the adduct SeF₄,2NbF₅. Crystals of this adduct are monoclinic, space group P2₁/c, a= 7·60, b= 17·38, c= 8·80 Å, β= 103·4°. The structure was refined by three-dimensional least-squares methods, to R 0·093 for 1330 reflections. The molecular geometry is consistent with the ionic formulation [SeF₃]⁺[Nb₂F₁₁]^–, with substantial interaction between the ions through fluorine bridging. This interaction leads to a much distorted octahedral co-ordination of selenium by fluorine atoms.