Niobium Chemical Properties

Niobium is stable in air at room temperature, and is not completely oxidized when red hot in oxygen. At high temperatures, it directly chemically combines with sulfur, nitrogen and carbon, and can form alloys with titanium, zirconium, hafnium and tungsten. It does not act with inorganic acids or bases, and is not soluble in aqua regia, but is soluble in hydrofluoric acid.
Niobium metal is extremely stable in air at room temperature and does not interact with air. Although it has a high melting point in the singlet state (2468°C), it has a lower density than other refractory metals. Niobium is also resistant to various types of erosion and forms dielectric oxide layers.
Niobium is less electropositive than the element zirconium located to its left. Its atoms are almost the same size as those of the element tantalum, which is located below it, due to the contraction effect of the lanthanides. This makes niobium chemically very similar to tantalum. Although its corrosion resistance is not as high as Tantalum's, it is cheaper and more common, so it is often used as a substitute for Tantalum in less demanding situations, such as as a coating material for chemical tanks in chemical plants.