Niobium, with the chemical symbol Nb and the atomic number 41, is a transition metal element. Niobium is a shiny grey metal. High-purity niobium metal has high ductility, but becomes harder as the impurity content increases. Niobium has a low capture cross section for thermal neutrons, so it is quite useful in the nuclear industry.

1. Niobium is stable in air at room temperature and does not completely oxidize when heated in oxygen.

2. It combines directly with sulfur, nitrogen and carbon at high temperatures and can form alloys with titanium, zirconium, hafnium and tungsten.

3. It does not interact with inorganic acids or bases, nor does it dissolve in aqua regia, but it dissolves in hydrofluoric acid.

4. Niobium is also resistant to various types of corrosion and can form a dielectric oxide layer.