Cobalt Metal is a actinic aspect with attribute Co and diminutive amount 27. It is begin by itself alone in chemically accumulated form. The chargeless element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
Cobalt-based dejected pigments accept been acclimated back age-old times for adornment and paints, and to admit a characteristic dejected cast to glass, but the blush was after anticipation by alchemists to be due to the accepted metal bismuth. Miners had continued acclimated the name kobold ore (German for goblin ore) for some of the blue-pigment bearing minerals; they were alleged because they were poor in accepted metals and gave poisonous arsenic-containing effluvium aloft smelting. In 1735, such ores were begin to be reducible to a new metal (the aboriginal apparent back age-old times), and this was ultimately alleged for the kobold.
Nowadays, some azure is produced accurately from assorted metallic-lustered ores, for archetype cobaltite (CoAsS), but the capital antecedent of the aspect is as a by-product of chestnut and nickel mining. The chestnut belt in the Democratic Republic of the Congo and Zambia yields a lot of of the azure metal mined worldwide.
Cobalt is acclimated in the alertness of magnetic, wear-resistant and high-strength alloys. Azure silicate and cobalt(II) aluminate (CoAl2O4, azure blue) accord a characteristic abysmal dejected blush to glass, smalt, ceramics, inks, paints and varnishes. Azure occurs by itself as alone one abiding isotope, cobalt-59. Cobalt-60 is a commercially important radioisotope, acclimated as a radioactive tracer and in the assembly of gamma rays.
Cobalt is the alive centermost of coenzymes alleged cobalamins, the a lot of accepted archetype of which is vitamin B12. As such it is an capital trace comestible mineral for all animals. Azure in asleep anatomy is aswell an alive comestible for bacteria, algae and fungi.
Characteristics
Cobalt is a ferromagnetic metal with a specific gravity of 8.9. Pure cobalt is not found in nature, but compounds of cobalt are common. Small amounts of it are found in most rocks, soil, plants and animals. The Curie temperature is 1115 °C and the magnetic moment is 1.6–1.7 Bohr magnetons per atom. In nature, it is frequently associated with nickel, and both are characteristic minor components of meteoric iron. Cobalt has a relative permeability two thirds that of iron. Metallic cobalt occurs as two crystallographic structures: hcp and fcc. The ideal transition temperature between the hcp and fcc structures is 450 °C, but in practice, the energy difference is so small that random intergrowth of the two is common.
Cobalt is a weakly reducing metal that is protected from oxidation by a passivating oxide film. It is attacked by halogens and sulfur. Heating in oxygen produces Co3O4 which loses oxygen at 900 °C to give the monoxide CoO.
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