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Cobalt is a chemical element in the periodic table that has the symbol Co and atomic number 27.
Cobalt is a hard ferromagnetic silver-white element. The Curie temperature is of 1388 K with 1.6~1.7 Bohr magnetons per atom. It is frequently associated with nickel, and both are characteristic ingredients of meteoric iron. Mammals require small amounts of cobalt salts. Cobalt-60, an artificially produced radioactive isotope of cobalt, is an important radioactive tracer and cancer-treatment agent. Cobalt has a relative permeability two thirds that of iron. Metallic cobalt commonly presents a mixture of two crystallographic structures hcp and fcc with a transition temperature hcp→fcc of 722 K.
Common oxidation states of cobalt include +2, and +3, though +1 is also seen.
Co-60 is useful as a gamma ray source partially because it can be produced - in known quantity, and very large amounts - by simply exposing natural cobalt to neutrons in a reactor for a given time.
Cobalt-60 (Co-60 or 60Co) is a radioactive metal that is used in radiotherapy. It produces two gamma rays with energies of 1.17 MeV and 1.33 MeV. The 60Co source is about 2 cm in diameter and as a result produces a geometric penumbra, making the edge of the radiation field fuzzy. The metal has the unfortunate habit of producing a fine dust, causing problems with radiation protection. The 60Co source is useful for about 5 years but even after this point is still very radioactive, and so cobalt machines have fallen from favor in the Western world where linacs are common. The first 60Co therapy machine (the "cobalt bomb") was built and first used in Canada. In fact the first machine is on display in the Saskatoon Cancer Centre – look up when entering the lobby. The second machine is out beside the walkway into the Centre.
Cobalt was known in ancient times through its compounds, which would color glass a rich blue.
George Brandt (1694-1768) is credited with the discovery of cobalt. The date of discovery varies depending on the source, but is between 1730 and 1737. He was able to show that cobalt was the source of the blue color in glasses, which previously had been attributed to the bismuth found with cobalt.
During the 19th century, cobalt blue was produced at the Norwegian Blaafarveværket (70-80 % of world production), led by the Prussian industrialist Benjamin Wegner.
In 1938, John Livingood and Glenn Seaborg discovered cobalt-60.
The word cobalt comes from the German kobalt or kobold, meaning evil spirit, the metal being so called by miners, because it was poisonous and troublesome (it polluted and degraded the other mined elements, like nickel). Other sources cite the origin as stemming from silver miners' belief that cobalt had been placed by kobolds who had stolen the silver. Some also think the name may derive from Greek kobalos, which means 'mine', and which may have common roots with kobold, goblin, and cobalt.
Cobalt in small amounts is essential to many living organisms, including humans. Having 0.13 to 0.30 mg/kg of cobalt in soils markedly improves the health of grazing animals. Cobalt is a central component of the vitamin cobalamin, or vitamin B-12.
Cobalt is not found as a free metal and is generally found in the form of ores. Cobalt is usually not mined alone, and tends to be produced as a by-product of nickel and copper mining activities. The main ores of cobalt are cobaltite, erythrite, glaucodot, and skutterudite. The world's major producers of cobalt are the Democratic Republic of the Congo, mainland China, Zambia, Russia and Australia. It is also found in Finland, Azerbaijan, and Kazakhstan. It is also produced in the town of Cobalt, Ontario as a byproduct of the silver mining.
Due to the various oxidation states, there is an abundant number of compounds. Oxides are antiferromagnetic at low temperature CoO (Neel temperature: 291 K) and Co3O4 (Neel temperature: 40 K).
Naturally occurring cobalt is composed of 1 stable isotope, 59-Co (59Co). 22 radioisotopes have been characterized with the most stable being 60Co with a half-life of 5.2714 years, 57-Co (57Co) with a half-life of 271.79 days, and 56-Co (56Co) with a half-life of 77.27 days, and 58-Co (58Co) with a half life of 70.86 days. All of the remaining radioactive isotopes have half-lifes that are less than 18 hours and the majority of these have half lives that are less than 1 second. This element also has 4 meta states, all of which have half lives less than 15 minutes.
The isotopes of cobalt range in atomic weight from 50 amu (50Co) to 73 amu (73Co). The primary decay mode before the most abundant stable isotope, 59Co, is electron capture and the primary mode after is beta decay. The primary decay products before 59Co are element 26 (iron) isotopes and the primary products after are element 28 (nickel) isotopes.
Powdered cobalt in metal form is a fire hazard. Cobalt compounds should be handled with care due to cobalt's slight toxicity.
Cobalt-60 is a powerful gamma ray emitter and exposure to 60Co is therefore a cancer risk. Ingestion of 60Co will lead to incorporation of some cobalt into tissues, which is released very slowly. Cobalt-60 is a risk factor in a nuclear confrontation because neutron emissions will convert iron into this isotope. Some nuclear weapon designs could intentionally increase the amount of Cobalt-60 dispersed as nuclear fallout – this is sometimes called a dirty bomb or cobalt bomb, once predicted by a leading scientist as being capable of wiping out all life on earth. The risk in the absence of a nuclear war comes from improper handling (or theft) of medical radiotherapeutic units. Nevertheless, the gamma radiation emitted from cobalt-60 is used to kill bacteria on fruit and vegetables thus increasing their shelf life. This process is referred to as irradiation.
Cobalt was also the name of Sun Microsystems' mainly rack-mounted, Intel and Linux based, server appliance line. Previously known as Cobalt Systems, this Internet appliance company was acquired by Sun in 2000. In the third quarter of 2003 Sun discountinued their Cobalt line in favor of the AMD based Sun Fire line.
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In the third quarter of 2003 Sun discountinued their Cobalt line in favor of the AMD based Sun Fire line. Other entities and concepts named crown include:. Previously known as Cobalt Systems, this Internet appliance company was acquired by Sun in 2000. In first-person shooters, crowning is the act of shooting an opponent in the back of the head with a shotgun, and is considered a grave humiliation. Cobalt was also the name of Sun Microsystems' mainly rack-mounted, Intel and Linux based, server appliance line. Crown is also the name of several currencies, originally bearing this symbol of the emitting monarchy (or modelled after such a coin) :. This process is referred to as irradiation. Crown names several entities associated with monarchy:. Nevertheless, the gamma radiation emitted from cobalt-60 is used to kill bacteria on fruit and vegetables thus increasing their shelf life. Crown (comics), an enemy of Spider-Man. The risk in the absence of a nuclear war comes from improper handling (or theft) of medical radiotherapeutic units. The Crown (German:Diu Crône) is an Arthurian romance. Some nuclear weapon designs could intentionally increase the amount of Cobalt-60 dispersed as nuclear fallout – this is sometimes called a dirty bomb or cobalt bomb, once predicted by a leading scientist as being capable of wiping out all life on earth. Bank Arena, an indoor arena in Cincinnati, Ohio. Cobalt-60 is a risk factor in a nuclear confrontation because neutron emissions will convert iron into this isotope. "The Crown" is another name for the U.S. Ingestion of 60Co will lead to incorporation of some cobalt into tissues, which is released very slowly. Toyota Crown, a Toyota car. Cobalt-60 is a powerful gamma ray emitter and exposure to 60Co is therefore a cancer risk. Ford Crown Victoria, a Ford car. Cobalt compounds should be handled with care due to cobalt's slight toxicity. Crown Hall, a famous work of modern architecture. Powdered cobalt in metal form is a fire hazard. The Crown (band), is a metal band. The primary decay products before 59Co are element 26 (iron) isotopes and the primary products after are element 28 (nickel) isotopes. Crown of Thorns. The primary decay mode before the most abundant stable isotope, 59Co, is electron capture and the primary mode after is beta decay. Crown (game), a computer game. The isotopes of cobalt range in atomic weight from 50 amu (50Co) to 73 amu (73Co). Crown (dentistry), a dental treatment. This element also has 4 meta states, all of which have half lives less than 15 minutes. Crown (botany), the branching leaf bearing portion of a tree. All of the remaining radioactive isotopes have half-lifes that are less than 18 hours and the majority of these have half lives that are less than 1 second. Crown (cards), a "fifth" suit in playing cards. 22 radioisotopes have been characterized with the most stable being 60Co with a half-life of 5.2714 years, 57-Co (57Co) with a half-life of 271.79 days, and 56-Co (56Co) with a half-life of 77.27 days, and 58-Co (58Co) with a half life of 70.86 days. Crown (anatomy), the top of the head. Naturally occurring cobalt is composed of 1 stable isotope, 59-Co (59Co). Crown Records, a record label. Oxides are antiferromagnetic at low temperature CoO (Neel temperature: 291 K) and Co3O4 (Neel temperature: 40 K). Crown International, Elkhart, Indiana, tape recorder and amplifier manufacturer. Due to the various oxidation states, there is an abundant number of compounds. Bonifacius, Minnesota. It is also produced in the town of Cobalt, Ontario as a byproduct of the silver mining. Crown College (Minnesota), a small private college in St. It is also found in Finland, Azerbaijan, and Kazakhstan. Crown College (California), one of the residential colleges at the University of California, Santa Cruz. The world's major producers of cobalt are the Democratic Republic of the Congo, mainland China, Zambia, Russia and Australia. Crown of the Polish Kingdom, territories of the Kingdom of Poland. The main ores of cobalt are cobaltite, erythrite, glaucodot, and skutterudite. the Swedish crown. Cobalt is usually not mined alone, and tends to be produced as a by-product of nickel and copper mining activities. the Norwegian crown. Cobalt is not found as a free metal and is generally found in the form of ores. the Icelandic crown. Cobalt is a central component of the vitamin cobalamin, or vitamin B-12. the Estonian crown. Having 0.13 to 0.30 mg/kg of cobalt in soils markedly improves the health of grazing animals. the Faroese crown. Cobalt in small amounts is essential to many living organisms, including humans. the Danish crown. Some also think the name may derive from Greek kobalos, which means 'mine', and which may have common roots with kobold, goblin, and cobalt. the Slovak crown. Other sources cite the origin as stemming from silver miners' belief that cobalt had been placed by kobolds who had stolen the silver. the Czech crown. The word cobalt comes from the German kobalt or kobold, meaning evil spirit, the metal being so called by miners, because it was poisonous and troublesome (it polluted and degraded the other mined elements, like nickel). the Slovak crown in WWII. In 1938, John Livingood and Glenn Seaborg discovered cobalt-60. the Czechoslovak crown. During the 19th century, cobalt blue was produced at the Norwegian Blaafarveværket (70-80 % of world production), led by the Prussian industrialist Benjamin Wegner. the Austro-Hungarian crown. He was able to show that cobalt was the source of the blue color in glasses, which previously had been attributed to the bismuth found with cobalt. the British crown. The date of discovery varies depending on the source, but is between 1730 and 1737. Crowning, a Russian novel. George Brandt (1694-1768) is credited with the discovery of cobalt. Compare Crown colony, Crown land. Cobalt was known in ancient times through its compounds, which would color glass a rich blue. The Crown, a term used to separate the government authority and property of the government from the personal influence and private assets held by the current Monarch of a kingdom. The second machine is out beside the walkway into the Centre. A crown (headgear), the headgear worn by a monarch, other high dignitaries, divinities etcetera. In fact the first machine is on display in the Saskatoon Cancer Centre – look up when entering the lobby. The first 60Co therapy machine (the "cobalt bomb") was built and first used in Canada. The 60Co source is useful for about 5 years but even after this point is still very radioactive, and so cobalt machines have fallen from favor in the Western world where linacs are common. The metal has the unfortunate habit of producing a fine dust, causing problems with radiation protection. The 60Co source is about 2 cm in diameter and as a result produces a geometric penumbra, making the edge of the radiation field fuzzy. It produces two gamma rays with energies of 1.17 MeV and 1.33 MeV. Cobalt-60 (Co-60 or 60Co) is a radioactive metal that is used in radiotherapy. Co-60 is useful as a gamma ray source partially because it can be produced - in known quantity, and very large amounts - by simply exposing natural cobalt to neutrons in a reactor for a given time. Common oxidation states of cobalt include +2, and +3, though +1 is also seen. Metallic cobalt commonly presents a mixture of two crystallographic structures hcp and fcc with a transition temperature hcp→fcc of 722 K. Cobalt has a relative permeability two thirds that of iron. Cobalt-60, an artificially produced radioactive isotope of cobalt, is an important radioactive tracer and cancer-treatment agent. Mammals require small amounts of cobalt salts. It is frequently associated with nickel, and both are characteristic ingredients of meteoric iron. The Curie temperature is of 1388 K with 1.6~1.7 Bohr magnetons per atom. Cobalt is a hard ferromagnetic silver-white element. . Cobalt is a chemical element in the periodic table that has the symbol Co and atomic number 27. London celebrates 50 years of Cobalt-60 Radiotherapy. WebElements.com – Cobalt. National Pollutant Inventory - Cobalt fact sheet. Cobalt is the name of a current line of cars from Chevrolet. Los Alamos National Laboratory - Cobalt. It is used in industrial radiography to detect structural flaws in metal parts. It is used in radiation treatment of foods for sterilization (cold pasteurization). It is used in radiotherapy. Cobalt-60 has multiple uses as a gamma ray source:
Battery electrodes. Pigments (cobalt blue and cobalt green). Ground coats for porcelain enamels. Drying agents for paints, varnishes, and inks. electroplating because of its appearance, hardness, and resistance to oxidation. Catalysts for the petroleum and chemical industries. Alnico magnets. Magnets and magnetic recording media.
Cemented carbides (also called hard metals) and diamond tools. High-speed steels. Corrosion- and wear-resistant alloys. Superalloys, for parts in gas turbine aircraft engines. Alloys, such as:
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