Niobium(V) fluoride, also known as niobium pentafluoride, is the inorganic compound with the formula NbF5. It is a colorless solid.[1]

Preparation and structure

Niobium pentafluoride is obtained by treatment of any niobium compound with fluorine:[2]

2 Nb + 5 F2 → 2 NbF5
2 NbCl5 + 5 F2 → 2 NbF5 + 5 Cl2

As shown by X-ray crystallography, the solid consists of tetramers [NbF5]4. This structure is related to that for WOF4.[3]

Reactions

It reacts with hydrogen fluoride to give H2NbF7, a superacid. In hydrofluoric acid, NbF5 converts to [NbF7]2- and [NbF5O]2-. The relative solubility of K2[MFO] (M = Nb, Ta) is the basis of the Marignac process for separation of Nb and Ta.

NbCl5 forms a dimeric structure (edge-shared bioctahedron) in contrast to the corner-shared tetrameric structure of the fluoride.

External links

References

  1. ^ Joachim Eckert; Hermann C. Starck (2005). "Niobium and Niobium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a17_251. ISBN 3527306730.
  2. ^ Homer F. Priest (1950). "Anhydrous Metal Fluorides". Inorganic Syntheses. Vol. 3. p. 171. doi:10.1002/9780470132340.ch47.
  3. ^ Edwards, A. J. (1964). "717. The structures of niobium and tantalum pentafluorides". Journal of the Chemical Society (Resumed): 3714. doi:10.1039/jr9640003714.