Heating in oxygen produces Co 3O 4 which loses oxygen at 900 ☌ (1,650 ☏) to give the monoxide CoO. Ĭobalt is a weakly reducing metal that is protected from oxidation by a passivating oxide film. The ideal transition temperature between the hcp and fcc structures is 450 ☌ (842 ☏), but in practice the energy difference between them is so small that random intergrowth of the two is common. Metallic cobalt occurs as two crystallographic structures: hcp and fcc. Cobalt has a relative permeability two-thirds that of iron. The Curie temperature is 1,115 ☌ (2,039 ☏) and the magnetic moment is 1.6–1.7 Bohr magnetons per atom. Cobalt in inorganic form is also a micronutrient for bacteria, algae, and fungi.Ĭharacteristics A block of electrolytically refined cobalt (99.9% purity) cut from a large plateĬobalt is a ferromagnetic metal with a specific gravity of 8.9. Vitamin B 12, the best-known example of the type, is an essential vitamin for all animals. Cobalt-60 is a commercially important radioisotope, used as a radioactive tracer and for the production of high-energy gamma rays.Ĭobalt is the active center of a group of coenzymes called cobalamins.
Cobalt occurs naturally as only one stable isotope, cobalt-59. The compounds cobalt silicate and cobalt(II) aluminate (CoAl 2O 4, cobalt blue) give a distinctive deep blue color to glass, ceramics, inks, paints and varnishes. Ĭobalt is primarily used in lithium-ion batteries, and in the manufacture of magnetic, wear-resistant and high-strength alloys. World production in 2016 was 116,000 tonnes (114,000 long tons 128,000 short tons) (according to Natural Resources Canada), and the DRC alone accounted for more than 50%. The Copperbelt in the Democratic Republic of the Congo (DRC) and Zambia yields most of the global cobalt production. The element is, however, more usually produced as a by-product of copper and nickel mining. Today, some cobalt is produced specifically from one of a number of metallic-lustered ores, such as cobaltite (CoAsS). In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), and this was ultimately named for the kobold. Miners had long used the name kobold ore ( German for goblin ore) for some of the blue pigment-producing minerals they were so named because they were poor in known metals and gave off poisonous arsenic-containing fumes when smelted.
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The free element, produced by reductive smelting, is a hard, lustrous, silver metal.Ĭobalt-based blue pigments ( cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was for a long time thought to be due to the known metal bismuth. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron.
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