Interaction between uranium pentafluoride and the pentafluorides of vanadium, arsenic, niobium, tantalum, and bismuth, and the tetrafluoride of sulphur

Abstract

The interaction of UF₅ with SF₄, SF₄O, and some Lewis-acid pentafluorides of various strengths has been studied. In anhydrous HF solutions, SF₄ was shown to yield an adduct of composition 3UF₅·SF₄ in which both ionic and fluorine-bridged species are present. The pentafluorides of arsenic, tantalum, and niobium combine with UF₅ to give adducts of composition 1.5 UF₅·AsF₅, UF₅·2TaF₅, and UF₅·2NbF₅, respectively. The arsenic derivative is stable at room temperature only under a pressure of AsF₅, whereas the tantalum and niobium adducts decompose at higher temperature forming UF₅·TaF₅ and UF₅·NbF₅, respectively. Vibrational spectroscopic study of the pentafluoride adducts of UF₅has shown that they consist of covalent fluorine-bridged species. Uranium pentafluoride is fluorinated at room temperature by VF₅ and by BiF₅ in anhydrous HF.