Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) 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.
- Niobium is used with iron and other elements in stainless steel alloys and also in alloys with a variety of nonferrous metals, such as zirconium,
Niobium alloys are strong and are often used in pipeline construction.
The metal is used in superalloys for jet engines and heat resistant equipment.
Niobium is also used for jewelry. At cryogenic temperatures, niobium is a superconductor.
- Niobium has no known biological role. While niobium dust is an eye and skin irritant and a potential fire hazard, elemental niobium on a larger scale is physiologically inert (and thus hypoallergenic) and harmless. It is frequently used in jewelry and has been tested for use in some medical implants.
Niobium-containing compounds are rarely encountered by most people, but some are toxic and should be treated with care. The short- and long-term exposure to niobates and niobium chloride, two chemicals that are water-soluble, have been tested in rats. Rats treated with a single injection of niobium pentachloride or niobates show a median lethal dose (LD50) between 10 and 100 mg/kg. For oral administration the toxicity is lower; a study with rats yielded a LD50 after seven days of 940 mg/kg.
Nb, atomic number 41
Source: Wikipedia, https://en.wikipedia.org/wiki/Niobium#Other_uses