Niobium is stable in the air at room temperature, and is not completely oxidized when it is red hot in oxygen, and is directly combined with sulfur, nitrogen and carbon at high temperature, and can form alloys with titanium, zirconium, hafnium and tungsten. It does not interact with inorganic acids or bases, nor is it soluble in aqua regia, but it 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 higher melting point (2468°C) in its elemental state, its density is lower than that of other refractory metals. Niobium also resists various attacks and can form a dielectric oxide layer.
Niobium has a lower electropositivity than the zirconium element located to its left. Its atomic size is almost the same as that of the tantalum element below it, which is due to the lanthanide shrinkage effect. This makes the chemical properties of niobium very similar to tantalum. Although it is not as resistant to corrosion as tantalum, it is less expensive and more common, so it is often used as a substitute for tantalum in less demanding situations, such as as as coating material in chemical tanks in chemical plants.