Editing Period 5 element (section)

===Niobium===
{{main|Niobium}}

'''Niobium''', or '''columbium''', is a [[chemical element]] with the symbol '''Nb''' and [[atomic number]] 41. It is a soft, grey, [[ductile]] [[transition metal]], which is often found in the [[pyrochlore]] mineral, the main commercial source for niobium, and [[columbite]]. The name comes from [[Greek mythology]]: ''[[Niobe]]'', daughter of ''[[Tantalus]]''.

Niobium has physical and chemical properties similar to those of the element [[tantalum]], and the two are therefore difficult to distinguish. The English chemist [[Charles Hatchett]] reported a new element similar to tantalum in 1801, and named it columbium. In 1809, the English chemist [[William Hyde Wollaston]] wrongly concluded that tantalum and columbium were identical. The German chemist [[Heinrich Rose]] determined in 1846 that tantalum ores contain a second element, which he named niobium. In 1864 and 1865, a series of scientific findings clarified that niobium and columbium were the same element (as distinguished from tantalum), and for a century both names were used interchangeably. The name of the element was officially adopted as niobium in 1949.

It was not until the early 20th century that niobium was first used commercially. [[Brazil]] is the leading producer of niobium and [[ferroniobium]], an [[alloy]] of niobium and iron. Niobium is used mostly in alloys, the largest part in special [[steel]] such as that used in gas [[Pipeline transport|pipelines]]. Although alloys contain only a maximum of 0.1%, that small percentage of niobium improves the strength of the steel. The temperature stability of niobium-containing [[superalloy]]s is important for its use in [[jet engine|jet]] and [[rocket engine]]s. Niobium is used in various [[Superconductivity|superconducting]] materials. These [[Type-II superconductor|superconducting alloys]], also containing [[titanium]] and [[tin]], are widely used in the [[superconducting magnet]]s of [[Magnetic resonance imaging|MRI scanners]]. Other applications of niobium include its use in welding, nuclear industries, electronics, optics, [[numismatics]] and jewelry. In the last two applications, niobium's low toxicity and ability to be colored by [[Anodizing|anodization]] are particular advantages.