Niobium(V) fluoride
IUPAC names
Niobium(V) fluoride
Niobium pentafluoride
3D model (JSmol)
ECHA InfoCard 100.029.109 Edit this at Wikidata
EC Number
  • 232-020-2
  • InChI=1S/5FH.Nb/h5*1H;/q;;;;;+5/p-5
  • F[Nb](F)(F)(F)F
Molar mass 187.89839 g·mol−1
Appearance colorless hygroscopic solid
Density 3.293 g/cm3
Melting point 72 to 73 °C (162 to 163 °F; 345 to 346 K)
Boiling point 236 °C (457 °F; 509 K)
Solubility slightly soluble in chloroform, carbon disulfide, sulfuric acid
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
H302, H312, H314, H332
P260, P261, P264, P270, P271, P280, P301+P312, P301+P330+P331, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P363, P405, P501
Flash point Non-flammable
Related compounds
Other anions
Niobium(V) chloride
Niobium(V) bromide
Niobium(V) iodide
Other cations
Vanadium(V) fluoride
Tantalum(V) fluoride
Related niobium fluorides
Niobium(III) fluoride
Niobium(IV) fluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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]


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.


  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.