Chemical reactions of the elements
Reaction of niobium with air
Niobium does not react with air under normal conditions. The surface of niobium metal is protected by a thin oxide layer.
Reaction of niobium with water
Niobium does not react with water under normal conditions. The surface of niobium metal is protected by a thin oxide layer.
Reaction of niobium with the halogens
Niobium does react with the halogens upon warming to form niobium(V) halides. So, niobium reacts with fluorine, F2, chlorine, Cl2, bromine, I2, and iodine, I2, to form respectively niobium(V) bromide, NbF5, niobium(V) chloride, NbCl5, niobium(V) bromide, NbBr5, and niobium(V) iodide, NbI5.
2Nb(s) + 5F2(g) → NbF5(s) [white]
2Nb(s) + 5Cl2(g) → NbCl5(l) [yellow]
2Nb(s) + 5Br2(g) → NbBr5(s) [orange]
2Nb(s) + 5I2(g) → NbI5(s) [brass coloured]
Reaction of niobium with acids
Niobium appears not to be attacked by many acids at room temperature but does dissolve in hydrofluoric acid, HF, or in a mixture of HF and nitric acid, HNO3.
Reaction of niobium with bases
Niobium metal is largely resistant to attack by molten alkali but will dissolve slowly.