physical property

Niobium is a gray white metal with a melting point of 2468 ℃, a boiling point of 4742 ℃, and a density of 8.57 grams per cubic centimeter. Niobium is a shiny gray metal with paramagnetism, belonging to the 5 groups on the periodic table of elements. High purity niobium metal has high ductility, but it hardens with increasing impurity content. The arrangement of its Z outer electron layer is very different from the other 5 group elements. The same phenomenon also occurs on ruthenium (44), rhodium (45), and palladium (46) elements before and after.

Niobium exhibits superconductive properties at low temperatures. At standard atmospheric pressure, its critical temperature is 9.2K, which is the highest among all single substance superconductors. Its magnetic penetration depth is also the highest among all elements. Niobium is one of the three types of elemental type II superconductors, with the other two being vanadium and technetium. The purity of niobium metal greatly affects its superconducting properties.

Niobium has a low capture cross-section for thermal neutrons, making it quite useful in the nuclear industry.

chemical property

At room temperature, niobium is stable in air and does not completely oxidize when red hot in oxygen. It directly combines with sulfur, nitrogen, and carbon at high temperatures and can form alloys with titanium, zirconium, hafnium, and tungsten. It does not react with inorganic acids or bases, nor is it soluble in aqua regia, but it is soluble in hydrofluoric acid. The oxidation states of niobium are -1,+2,+3,+4, and+5, among which compound Z with a+5 valence is stable.

Niobium metal is extremely stable in air at room temperature and does not interact with air. Although it has a higher melting point in the elemental state (2468 ° C), its density is lower than other refractory metals. Niobium can also resist various types of erosion and form a dielectric oxide layer.

The electropositivity of niobium is lower than that of the zirconium element located on its left. Its atomic size is almost the same as the tantalum atom located below it, which is caused by the contraction effect of the lanthanide system. This makes the chemical properties of niobium very similar to that of tantalum. Although its corrosion resistance is not as high as tantalum, it is cheaper and more common, so it is commonly used as a substitute for tantalum in situations with lower requirements, such as as as as a coating material for chemical tanks in chemical factories.