Niobium

Niobium is a chemical element. It is sometimes named columbium. It has the chemical symbol Nb. It has the atomic number 41. It is a rare metal. Niobium is hard and grey. It is ductile. In chemistry it is placed in a group of metal elements named the transition metals. Niobium was discovered in a variety of a mineral called columbite (now called niobite). Niobite is an ore of niobium.^[1]

Niobium is considered a technology-critical element. It is used in alloys, such as to make special steels and strong welded joints. Less than 0.1% of Niobium significantly improves the strength of steel.^[2] It is in the superconducting alloys used in MRI scanners, which are one of the most important medical inventions of the modern age.

In 1801, Charles Hatchett claimed to have discovered a new chemical element in a sample from the United States. He named the mineral "columbite" and his element "columbium", after Columbia, another name for the United States.^[3] However, chemists were uncertain that columbium was a new element because of its similarity to tantalum. William Hyde Wollaston claimed that columbium and tantalum were the same element.^[4] Other chemists claimed that up to five new elements were in these minerals, one of which was named "niobium".

It took until 1864 to make pure tantalum and niobium and show there were only two elements in these minerals. One of these two elements was named "tantalum", but this showed that "niobium" and "columbium" were the same element. Americans preferred the name "columbium", while "niobium" was more common in Europe. Almost a hundred years later, IUPAC decided on the name niobium as part of an effort to make the names of chemical elements more universal.

Niobium and tantalum are in the same group, so their chemistry is very similar. Their ores make a solid solution series called coltan. Niobium and tantalum are both extracted from coltan by leaching.^[5] Pyrochlore is another important niobium ore, which can be reduced by aluminium or carbon to make ferroniobium..^[6][7]