Colorless monoclinic crystals; hygroscopic; density 3.293 g/cm3; melts at 72°C; vaporizes at 236°C; hydrolyzes in water forming hydrofluoric acid and fluoroniobic acid, H2NbOF5; soluble in alcohol, slightly soluble in chloroform, carbon disulfide and sulfuric acid.
Niobium(V) fluoride is used as a starting material to prepare other niobium compounds. It acts as an intermediate during the recovery of niobium metal.
Niobium pentafluoride is used in making other fluoro compounds of niobium.
Niobium pentafluoride is obtained as an intermediate during the recovery of niobium metal from its ores (See Niobium). It also can be prepared by direct fluorination of niobium metal at 250 to 300°C, either by fluorine gas or anhydrous hydrofluoric acid. The pentafluoride vapors are condensed in a pyrex or quartz tube from which it is sublimed at 120°C under vacuum and collected as colorless crystals.
Also, niobium pentafluroide can be prepared by the reaction of fluorine with niobium pentachloride: 2NbCl2 + 5F2 → 2NbF5 + 5Cl2.
