Cobalt#Batteries

File:Kobalt 13g.jpg refined cobalt (99.9% purity) cut from a large plate]]

Cobalt is a ferromagnetic metal with a specific gravity of 8.9. The Curie temperature is {{convert|1115|C}}{{cite book|author1 =Enghag, Per|chapter-url =https://books.google.com/books?id=aff7sEea39EC&pg=PA680|title =Encyclopedia of the elements: technical data, history, processing, applications|chapter = Cobalt|page =667|date =2004| publisher=Wiley |isbn =978-3-527-30666-4}} and the magnetic moment is 1.6–1.7 Bohr magnetons per atom.{{cite book|author1 = Murthy, V. S. R|chapter-url = https://books.google.com/books?id=fi_rnPJeTV8C&pg=PA381|title = Structure And Properties of Engineering Materials|chapter = Magnetic Properties of Materials|page = 381|date = 2003| publisher=McGraw-Hill Education (India) Pvt Limited |isbn = 978-0-07-048287-6}} Cobalt has a relative permeability two-thirds that of iron.{{cite book|url = https://books.google.com/books?id=opQjaSj2yIMC&pg=PA27|page = 27|title = Electromagnetic Shielding|isbn = 978-0-470-05536-6|author1 = Celozzi, Salvatore|author2 = Araneo, Rodolfo|author3 = Lovat, Giampiero|date = 1 May 2008| publisher=Wiley }} Metallic cobalt occurs as two crystallographic structures: hcp and fcc. The ideal transition temperature between the hcp and fcc structures is {{convert|450|C}}, but in practice the energy difference between them is so small that random intergrowth of the two is common.{{cite journal|last1 = Lee|first1 = B.|last2 = Alsenz|first2 = R.|last3 = Ignatiev|first3 = A.|last4 = Van Hove|first4 = M.|last5 = Van Hove|first5 = M. A.|title = Surface structures of the two allotropic phases of cobalt|journal = Physical Review B|volume = 17|pages = 1510–1520|date = 1978|doi = 10.1103/PhysRevB.17.1510|issue = 4|bibcode = 1978PhRvB..17.1510L }}{{cite web|url = http://www.americanelements.com/co.html|title = Properties and Facts for Cobalt|publisher = American Elements|access-date = 19 September 2008|archive-date = 2 October 2008|archive-url = https://web.archive.org/web/20081002060936/http://www.americanelements.com/co.html}}{{cite book|url = https://books.google.com/books?id=H8XVAAAAMAAJ| page = 45|title = Cobalt|publisher=Centre d'Information du Cobalt |location=Brussels|date = 1966}}

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 {{convert|900|C}} to give the monoxide CoO. The metal reacts with fluorine (F₂) at 520 K to give CoF₃; with chlorine (Cl₂), bromine (Br₂) and iodine (I₂), producing equivalent binary halides. It does not react with hydrogen gas (H₂) or nitrogen gas (N₂) even when heated, but it does react with boron, carbon, phosphorus, arsenic and sulfur.{{Housecroft3rd|page=722}} At ordinary temperatures, it reacts slowly with mineral acids, and very slowly with moist, but not dry, air.{{Citation needed|date=January 2021}}

{{Category see also|Cobalt compounds}}

Image:Cobalt tool tip - 02.jpg

Common oxidation states of cobalt include +2 and +3, although compounds with oxidation states ranging from −3 to +5 are also known. A common oxidation state for simple compounds is +2 (cobalt(II)). These salts form the pink-colored metal aquo complex {{chem|[Co|(H|2|O)|6|]|2+}} in water. Addition of chloride gives the intensely blue {{chem|[CoCl|4|]|2-}}. In a borax bead flame test, cobalt shows deep blue in both oxidizing and reducing flames.{{Cite book|url=https://books.google.com/books?id=7tfyCAAAQBAJ|title=Rutley's Elements of Mineralogy|last=Rutley|first=Frank|date=6 December 2012|publisher=Springer Science & Business Media|isbn=978-94-011-9769-4|page=40|language=en}}

Several oxides of cobalt are known. Green cobalt(II) oxide (CoO) has rocksalt structure. It is readily oxidized with water and oxygen to brown cobalt(III) hydroxide (Co(OH)₃). At temperatures of 600–700 °C, CoO oxidizes to the blue cobalt(II,III) oxide (Co₃O₄), which has a spinel structure.{{Greenwood&Earnshaw2nd|pages=1117–1119}} Black cobalt(III) oxide (Co₂O₃) is also known.{{cite book|page=107|title=The history and use of our earth's chemical elements: a reference guide|author=Krebs, Robert E.|edition=2nd|publisher=Greenwood Publishing Group|date=2006|isbn=0-313-33438-2}} Cobalt oxides are antiferromagnetic at low temperature: CoO (Néel temperature 291 K) and Co₃O₄ (Néel temperature: 40 K), which is analogous to magnetite (Fe₃O₄), with a mixture of +2 and +3 oxidation states.{{cite journal|last1=Petitto|first1=Sarah C.|last2=Marsh|first2=Erin M.|last3=Carson|first3=Gregory A.|last4=Langell|first4=Marjorie A.|title=Cobalt oxide surface chemistry: The interaction of CoO(100), Co3O4(110) and Co3O4(111) with oxygen and water|url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1021&context=chemistrylangell|journal=Journal of Molecular Catalysis A: Chemical|volume=281|issue=1–2|pages=49–58|date=2008|doi=10.1016/j.molcata.2007.08.023|s2cid=28393408 }}

The principal chalcogenides of cobalt are the black cobalt(II) sulfides, CoS₂ (pyrite structure), {{chem2|Co2S3}} (spinel structure), and CoS (nickel arsenide structure).{{rp|1118}}

File:Cobalt(II)-chloride-hexahydrate-sample.jpg

Four dihalides of cobalt(II) are known: cobalt(II) fluoride (CoF₂, pink), cobalt(II) chloride (CoCl₂, blue), cobalt(II) bromide (CoBr₂, green), cobalt(II) iodide (CoI₂, blue-black). These halides exist in anhydrous and hydrated forms. Whereas the anhydrous dichloride is blue, the hydrate is red.{{Greenwood&Earnshaw2nd|pages=1119–1120}}

The reduction potential for the reaction {{chem|Co|3+}} + e⁻ → {{chem|Co|2+}} is +1.92 V, beyond that for chlorine to chloride, +1.36 V. Consequently, cobalt(III) chloride would spontaneously reduce to cobalt(II) chloride and chlorine. Because the reduction potential for fluorine to fluoride is so high, +2.87 V, cobalt(III) fluoride is one of the few simple stable cobalt(III) compounds. Cobalt(III) fluoride, which is used in some fluorination reactions, reacts vigorously with water.

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The inventory of complexes is very large. Starting with higher oxidation states, complexes of Co(IV) and Co(V) are rare. Examples are found in caesium hexafluorocobaltate(IV) (Cs₂CoF₆) and potassium percobaltate (K₃CoO₄).{{cite book|author=Holleman, A. F.|author2=Wiberg, E.|author3=Wiberg, N.|title = Lehrbuch der Anorganischen Chemie|edition = 102nd|publisher = de Gruyter|date = 2007|language=de|isbn = 978-3-11-017770-1| pages = 1146–1152|chapter = Cobalt}}

Cobalt(III) forms a wide variety of coordination complexes with ammonia and amines, which are called ammine complexes. Examples include {{chem2|[Co(NH3)6](3+)}}, {{chem2|[Co(NH3)5Cl](2+)}} (chloropentamminecobalt(III)), and cis- and trans-{{chem2|[Co(NH3)4Cl2]+}}. The corresponding ethylenediamine complexes are also well known. Analogues are known where the halides are replaced by nitrite, hydroxide, carbonate, etc. Alfred Werner worked extensively on these complexes in his Nobel-prize winning work.{{cite journal|author = Werner, A. |title = Zur Kenntnis des asymmetrischen Kobaltatoms. V|journal = Chemische Berichte|date = 1912|volume = 45|pages = 121–130|doi = 10.1002/cber.19120450116|url = https://zenodo.org/record/1426471}} The robustness of these complexes is demonstrated by the optical resolution of tris(ethylenediamine)cobalt(III) ({{chem|[Co(en)|3|]|3+}}).{{cite book|chapter-url = https://books.google.com/books?id=9d893122U6kC&pg=PR31|pages = 31–33|chapter = Early Theories of Coordination Chemistry|title = Coordination chemistry|isbn = 978-3-527-31802-5|author1 = Gispert, Joan Ribas|date = 2008| publisher=Wiley |access-date = 27 June 2015|archive-date = 5 May 2016|archive-url = https://web.archive.org/web/20160505203708/https://books.google.com/books?id=9d893122U6kC&pg=PR31}}

Cobalt(II) forms a wide variety of complexes, but mainly with weakly basic ligands. The pink-colored cation hexaaquocobalt(II) {{chem2|[Co(H2O)6](2+)}} is found in several routine cobalt salts such as the nitrate and sulfate. Upon addition of excess chloride, solutions of the hexaaquo complex converts to the deep blue {{chem2|CoCl4(2−)}}, which is tetrahedral.

Softer ligands like triphenylphosphine form complexes with Co(II) and Co(I), examples being bis- and tris(triphenylphosphine)cobalt(I) chloride, {{chem2|CoCl2(PPh3)2}} and {{chem2|CoCl(PPh3)3}}. These Co(I) and Co(II) complexes represent a link to the organometallic complexes described below.

File:Tetrakis(1-norbornyl)cobalt(IV).png

{{Main|Organocobalt chemistry}}

Cobaltocene is a structural analog to ferrocene, with cobalt in place of iron. Cobaltocene is much more sensitive to oxidation than ferrocene. Cobalt carbonyl (Co₂(CO)₈) is a catalyst in carbonylation and hydrosilylation reactions. Vitamin B₁₂ (see below) is an organometallic compound found in nature and is the only vitamin that contains a metal atom. An example of an alkylcobalt complex in the otherwise uncommon +4 oxidation state of cobalt is the homoleptic complex tetrakis(1-norbornyl)cobalt(IV) (Co(1-norb)₄), a transition metal-alkyl complex that is notable for its resistance to β-hydrogen elimination, in accord with Bredt's rule. The cobalt(III) and cobalt(V) complexes {{chem|[Li(T|H|F)|4|]|+|[Co(1-norb)|4|]|-|}} and {{chem|[Co(1-norb)|4|]|+|[B|F|4|]|-|}} are also known.

{{Main|Isotopes of cobalt}}

⁵⁹Co is the only stable cobalt isotope and the only isotope that exists naturally on Earth. Twenty-two radioisotopes have been characterized: the most stable, ⁶⁰Co, has a half-life of 5.2714 years; ⁵⁷Co has a half-life of 271.8 days; ⁵⁶Co has a half-life of 77.27 days; and ⁵⁸Co has a half-life of 70.86 days. All the other radioactive isotopes of cobalt have half-lives shorter than 18 hours, and in most cases shorter than 1 second. This element also has 4 meta states, all of which have half-lives shorter than 15 minutes.{{NUBASE 2003}}

The isotopes of cobalt range in atomic weight from 50 u (⁵⁰Co) to 73 u (⁷³Co). The primary decay mode for isotopes with atomic mass unit values less than that of the only stable isotope, ⁵⁹Co, is electron capture and the primary mode of decay in isotopes with atomic mass greater than 59 atomic mass units is beta decay. The primary decay products below ⁵⁹Co are element 26 (iron) isotopes; above that the decay products are element 28 (nickel) isotopes.

Because ⁵⁹Co is a nucleus of spin 7/2 and 100% abundancy, it is possible to detect it using nuclear magnetic resonance spectroscopy.

{{cite book |vauthors=Chan J, Auyeung S |year=2000 |chapter=Cobalt-59 NMR spectroscopy |veditors=Webb GA |title=Annual Reports on NMR Spectroscopy |publisher=Elsevier |volume=41 |pages=1–54 |doi=10.1016/S0066-4103(00)41008-2 |isbn=978-0-12-505341-9}} The nucleus has a magnetic quadrupole moment. Among all NMR active nuclei, ⁵⁹Co has the largest chemical shift range and the chemical shift can be correlated with the spectrochemical series.{{cite journal |last1=Yamasaki |first1=A |year=1991 |title=Cobalt-59 Nuclear Magnetic Resonance Spectroscopy in Coordination Chemistry |journal=Journal of Coordination Chemistry |volume=24 |issue=3 |pages=211–260 |doi=10.1080/00958979109407886 }} Resonances are observed over a range of 20000 ppm, the width of the signals being up to 20 kHz. A widely used standard is potassium hexacyanocobaltate (0.1M {{chem2|K3Co(CN)6}} in {{chem2|D2O}}), which, due to its high symmetry, has a rather small line width. Systems of low symmetry can yield broadened signals to an extent that renders the signals unobservable in fluid phase NMR, but still observable in solid state NMR.

{{see also|Gnome#Cobalt ore}}

Many different stories about the origin of the word "cobalt" have been proposed. In one version the element cobalt was named after "{{lang|de|kobelt}}", the name which 16th century German silver miners had given to a nuisance type of ore which occurred that was corrosive and issued poisonous gas. Although such ores had been used for blue pigmentation since antiquity, the Germans at that time did not have the technology to smelt the ore into metal (cf. {{section link||History}} below).

The authority on such kobelt ore (Latinized as cobaltum or cadmia) at the time was Georgius Agricola. He was also the oft-quoted authority on the mine spirits called "{{lang|de|kobel}}" (Latinized as cobalus or pl. cobali) in a separate work.This passage from the separate work, de animantibus is translated in footnote by the {{harvp|Agricola|Hoovers trr.|1912}}, {{URL|1=https://books.google.com/books?id=MfFYAAAAYAAJ&pg=PA112 |2=p. 217, n26}}: "the Germans as well as the Greeks call cobalos".

Agricola did not make a connection between the similarly named ore and spirit. However, a causal connection (ore blamed on "kobel") was made by a contemporary,{{Refn|name="mathesius1562"|Lutheran reformist theologian Johannes Mathesius's sermon (1652) on the nuisance kobelt ore believed caused by a demon known to the masses as kobel. Quoted in English by the Hoovers,{{sfnp|Agricola|Hoovers trr.|1912|loc=p. 214, n21}} excerpted by Wothers.}} and a word origin connection (word "formed" from cobalus) made by a late 18th century writer.{{Refn|Johann Beckmann (Eng. tr. 1797), who did explicitly comment on the derivation of the word for "cobalt" ore as formed from kobel (Agricola's cobalus) has been cited by chemist Peter Wothers on this topic.}} Later, Grimms' dictionary (1868) noted the kobalt/kobelt ore was blamed on the mountain spirit ({{interlanguage link|Berggeist|de|lt=Bergmännchen}}{{efn|Grimm's dictionary more specifically calls it "spectral mountain manikin" ({{lang|de|gespenstisches Bergmännchen)}}, elsewhere ("Kobold" II) it is notes kobold also refers to Berggeist in bergmännisch (miners' lingo).}}) which was also held responsible for "stealing the silver and putting out an ore that caused poor mining atmosphere (Wetter) and other health hazards".

Grimms' dictionary entries equated the word "kobel" with "kobold", and listed it as a mere variant diminutive,{{Refn|Grimms dictionary states that kobalt and kobold are "the same word at its original source (ursprünglich)". Also, Grimm's entry in "kobold", III. ursprung, nebenformen, 3) a) lists kobel as a diminutive {{linktext|Nebenname}}.}} but the latter is defined in it as a household spirit. Whereas some of the more recent commentators prefer to characterize the ore's namesake kobelt (recté kobel) as a gnome.{{Refn|Actually, among "gnomes and goblins".}}{{Refn|The kobel was aka "bergmenlin" (mod. standard spelling {{lang|de|Bergmännlein, Bergmännchen}}) according to Agricola's gloss. Grimms dictionary also says the ores are caused by Bergmännchen sprites, but it thinks the miners call this "kobold", not distinguishable from "kobel". Whereas Lecouteux's dictionary defines "Bergmännchen" as "mine spirit" and admits "kobel" but not "kobld" as synonym. More recently, literature is found that does not hesitate to call the Bergmännchen a "gnome".}}

The early 20th century Oxford English Dictionary (1st edition, 1908) had upheld Grimm's etymology.{{Refn|group="lower-alpha"|Grimm derived and kobold from Greek kobalos, as aforestated; the OED concurred that kobold, kobelt (ore), kobel (mine spirit) were the same word.}} However, by around the same time in Germany, the alternate etymology not endorsed by Grimm (kob/kof "house, chamber" + walt "power, ruler") was being proposed as more convincing.

Somewhat later, Paul Kretschmer (1928) explained that while this "house ruler" etymology was the proper one that backed the original meaning of kobold as household spirit, a corruption later occurred introducing the idea of "mine demon" to it. The present edition of the Etymologisches Wörterbuch (25th ed., 2012) under "kobold" lists the latter, not Grimm's etymology, but still persists, under its entry for "kobalt", that while the cobalt ore may have got its name from "a type of mine spirit/demon" (daemon metallicus) while stating that this is "apparently" the kobold.

Joseph William Mellor (1935) also stated that cobalt may derive from kobalos ({{lang|grc|κόβαλος}}), though other theories had been suggested.

Several alternative etymologies that have been suggested, which may not involve a spirit (kobel or kobold) at all. Karl Müller-Fraureuth conjectured that kobelt derived from {{linktext|Kübel}}, a bucket used in mining, frequently mentioned by Agricola, namely the kobel/köbel (Latinized as modulus).Agricola (1546) {{URL|1=https://books.google.com/books?id=F6tlCB1PdJoC&pg=PA481|2=p. 481}}: {{langx|la|modulus}} {{=}} {{langx|de|Kobel}}

Another theory given by the Etymologisches Wörterbuch derives the term from {{Transliteration|grc|kōbathium}} or rather {{Transliteration|grc|cobathia}} ({{lang|grc|κωβάθια}}, "arsenic sulfide"Liddell and Scott (1940). A Greek–English Lexicon. s.v. "{{URL|1=https://www.perseus.tufts.edu/hopper/morph?l=kwba%2Fqia&la=greek&can=kwba%2Fqia0&prior=kaloka)gaqi/a |2=kwba/qia}}". Revised and augmented throughout by Sir Henry Stuart Jones with the assistance of Roderick McKenzie. Oxford: Clarendon Press. {{ISBN|0-19-864226-1}}. Online version retrieved 29 August 2024.) which occurs as noxious fumes.

An etymology from Slavonic {{Transliteration|sla|kowalti}} was suggested by Emanuel Merck (1902).

W. W. Skeat and J. Berendes construed {{lang|grc|κόβαλος}} as "parasite", i.e. as an ore parasitic to nickel, but this explanation is faulted for its anachronism since nickel was not discovered until 1751.{{Refn|"J. Berenedes" recté {{cite journal|last=Berendes |first=J. |author-link= |title=Die Namen der Elemente |journal=Chemiker-Zeitung |volume=23 |number=11 |date=8 February 1899 |url=https://babel.hathitrust.org/cgi/pt?id=njp.32101050964939&seq=129 |page=103}}}}

File:Early blue and white ware circa 1335 Jingdezhen.jpg

Cobalt compounds have been used for centuries to impart a rich blue color to glass, glazes, and ceramics. Cobalt has been detected in Egyptian sculpture, Persian jewelry from the third millennium BC, in the ruins of Pompeii, destroyed in 79 AD, and in China, dating from the Tang dynasty (618–907 AD) and the Ming dynasty (1368–1644 AD).[https://www.britannica.com/EBchecked/topic/123235/cobalt-Co Cobalt], Encyclopædia Britannica Online.

Cobalt has been used to color glass since the Bronze Age. The excavation of the Uluburun shipwreck yielded an ingot of blue glass, cast during the 14th century BC. Blue glass from Egypt was either colored with copper, iron, or cobalt. The oldest cobalt-colored glass is from the eighteenth dynasty of Egypt (1550–1292 BC). The source for the cobalt the Egyptians used is not known.

The word cobalt is derived from the 16th century German "{{lang|de|kobelt}}", a type of ore, as aforementioned. The first attempts to smelt those ores for copper or silver failed, yielding simply powder (cobalt(II) oxide) instead. Because the primary ores of cobalt always contain arsenic, smelting the ore oxidized the arsenic into the highly toxic and volatile arsenic oxide, adding to the notoriety of the ore.{{cite book|isbn = 978-0-202-36361-5|pages =254–256|chapter=Cobalt |chapter-url = https://books.google.com/books?id=UyE49SzKWHIC&pg=PA254|title = Metallurgy: 1863–1963|author1 = Dennis, W. H|date = 2010|publisher =AldineTransaction}} Paracelsus, Georgius Agricola, and Basil Valentine all referred to such silicates as "cobalt".{{cite web | url=https://books.google.com/books?id=uVsrAAAAYAAJ&dq=paracelsus+%22cobalt%22&pg=RA11-PA48 | title=Tariff Information Surveys on the Articles in Paragraph 1- of the Tariff Act of 1913 ... And Related Articles in Other Paragraphs | date=17 August 2023 }}

Swedish chemist Georg Brandt (1694–1768) is credited with discovering cobalt {{Circa|1735}}, showing it to be a previously unknown element, distinct from bismuth and other traditional metals. Brandt called it a new "semi-metal",Georg Brandt first showed cobalt to be a new metal in: G. Brandt (1735) "Dissertatio de semimetallis" (Dissertation on semi-metals), Acta Literaria et Scientiarum Sveciae (Journal of Swedish literature and sciences), vol. 4, pages 1–10.
See also: (1) G. Brandt (1746) "Rön och anmärkningar angäende en synnerlig färg—cobolt" (Observations and remarks concerning an extraordinary pigment—cobalt), Kongliga Svenska vetenskapsakademiens handlingar (Transactions of the Royal Swedish Academy of Science), vol. 7, pp. 119–130; (2) G. Brandt (1748) "Cobalti nova species examinata et descripta" (Cobalt, a new element examined and described), Acta Regiae Societatis Scientiarum Upsaliensis (Journal of the Royal Scientific Society of Uppsala), 1st series, vol. 3, pp. 33–41; (3) James L. Marshall and Virginia R. Marshall (Spring 2003) [https://web.archive.org/web/20100703175508/http://www.chem.unt.edu/Rediscovery/Riddarhyttan.pdf "Rediscovery of the Elements: Riddarhyttan, Sweden"]. The Hexagon (official journal of the Alpha Chi Sigma fraternity of chemists), vol. 94, no. 1, pages 3–8. naming it for the mineral from which he had extracted it.Weeks, M. E. (1968). Discovery of the elements. (H. M. Leicester, Ed.; 7th ed.). Journal of chemical education.

{{rp|153}} He showed that compounds of cobalt metal were the source of the blue color in glass, which previously had been attributed to the bismuth found with cobalt. Cobalt became the first metal to be discovered since the pre-historical period. All previously known metals (iron, copper, silver, gold, zinc, mercury, tin, lead and bismuth) had no recorded discoverers.{{cite journal|last1 = Weeks|first1 = Mary Elvira|author-link1=Mary Elvira Weeks|title = The discovery of the elements. III. Some eighteenth-century metals|journal = Journal of Chemical Education|volume = 9|issue = 1|page = 22|date = 1932|doi = 10.1021/ed009p22|bibcode = 1932JChEd...9...22W }}

During the 19th century, a significant part of the world's production of cobalt blue (a pigment made with cobalt compounds and alumina) and smalt (cobalt glass powdered for use for pigment purposes in ceramics and painting) was carried out at the Norwegian Blaafarveværket.{{cite book|last=Ramberg |first=Ivar B. |author-link= |title=The making of a land: geology of Norway|url=https://books.google.com/books?id=rMVNE0F2SckC&pg=PA98|access-date= 30 April 2011 |date=2008 |publisher=Geological Society |isbn=978-82-92394-42-7|page=98}}{{cite encyclopedia |entry=Cobalt |encyclopedia=Cyclopædia of useful arts & manufactures |editor=C. Tomlinson |entry-url=https://books.google.com/books?id=w_cGAAAAQAAJ&pg=PA400 |date=1852|pages=400–403}} The first mines for the production of smalt in the 16th century were located in Norway, Sweden, Saxony and Hungary. With the discovery of cobalt ore in New Caledonia in 1864, the mining of cobalt in Europe declined. With the discovery of ore deposits in Ontario, Canada, in 1904 and the discovery of even larger deposits in the Katanga Province in the Congo in 1914, mining operations shifted again. When the Shaba conflict started in 1978, the copper mines of Katanga Province nearly stopped production.{{cite web|url = http://pubs.usgs.gov/circ/2007/1294/paper1.html|title = Global Nonfuel Mineral Resources and Sustainability |first1 = Friedrich-Wilhelm|last1 = Wellmer|first2 = Jens Dieter|last2 = Becker-Platen|publisher = United States Geological Survey}}{{cite book|chapter-url = https://books.google.com/books?id=Xpypu9qqDncC&pg=PA75|isbn = 978-0-19-829104-6|pages = 75–78|chapter = cobalt|title = Global resources and international conflict: environmental factors in strategic policy and action|author1 = Westing, Arthur H|author2 = Stockholm International Peace Research Institute|date = 1986| publisher=Oxford University Press }} The impact on the world cobalt economy from this conflict was smaller than expected: cobalt is a rare metal, the pigment is highly toxic, and the industry had already established effective ways for recycling cobalt materials. In some cases, industry was able to change to cobalt-free alternatives.

In 1938, John Livingood and Glenn T. Seaborg discovered the radioisotope cobalt-60.{{cite journal| last1 =Livingood| first1 =J.| last2 =Seaborg| first2 =Glenn T.| title =Long-Lived Radio Cobalt Isotopes| journal =Physical Review| volume =53| pages =847–848| date =1938| doi =10.1103/PhysRev.53.847| issue =10|bibcode = 1938PhRv...53..847L }} This isotope was famously used at Columbia University in the 1950s to establish parity violation in radioactive beta decay.{{cite journal| last1 = Wu| first1 = C. S.| title = Experimental Test of Parity Conservation in Beta Decay| journal = Physical Review| volume = 105| pages = 1413–1415| date = 1957| doi = 10.1103/PhysRev.105.1413| issue = 4|bibcode = 1957PhRv..105.1413W | doi-access = free}}{{cite journal|journal =Acta Physica Polonica B|volume = 39|issue = 2|date = 2008|page = 251|title = The Downfall of Parity – the Revolution That Happened Fifty Years Ago|first =A. K.|last = Wróblewski|s2cid =34854662|bibcode = 2008AcPPB..39..251W }}

After World War II, the US wanted to guarantee the supply of cobalt ore for military uses (as the Germans had been doing) and prospected for cobalt within the US. High purity cobalt was highly sought after for its use in jet engines and gas turbines.{{Citation |last1=Roberts |first1=Stephen |author-link= |title=Cobalt |date=6 January 2014 |url=https://onlinelibrary.wiley.com/doi/10.1002/9781118755341.ch6 |work=Critical Metals Handbook |pages=122–149 |editor-last=Gunn |editor-first=Gus |access-date=1 December 2023 |edition=1 |publisher=Wiley |language=en |doi=10.1002/9781118755341.ch6 |isbn=978-0-470-67171-9 |last2=Gunn |first2=Gus}} An adequate supply of the ore was found in Idaho near Blackbird canyon. Calera Mining Company started production at the site.{{cite journal | url = https://books.google.com/books?id=kNwDAAAAMBAJ&pg=PA65 | title = Richest Hole in the Mountain | journal = Popular Mechanics | year = 1952 | pages = 65–69}}

Cobalt demand has further accelerated in the 21st century as an essential constituent of materials used in rechargeable batteries, superalloys, and catalysts. It has been argued that cobalt will be one of the main objects of geopolitical competition in a world running on renewable energy and dependent on batteries, but this perspective has also been criticised for underestimating the power of economic incentives for expanded production.{{Cite journal|last=Overland|first=Indra|date=1 March 2019|title=The geopolitics of renewable energy: Debunking four emerging myths|journal=Energy Research & Social Science|volume=49|pages=36–40|doi=10.1016/j.erss.2018.10.018|issn=2214-6296|doi-access=free|bibcode=2019ERSS...49...36O |hdl=11250/2579292|hdl-access=free}}

The stable form of cobalt is produced in supernovae through the r-process.{{cite journal|bibcode = 1980SvAL....6...61P|title=Creation of the Iron-Group Elements in a Supernova Explosion|author=Ptitsyn, D. A.|author2=Chechetkin, V. M.|journal=Soviet Astronomy Letters|volume= 6|date=1980|pages=61–64}} It comprises 0.0029% of the Earth's crust. Except as recently delivered in meteoric iron, free cobalt (the native metal) is not found on Earth's surface because of its tendency to react with oxygen in the atmosphere. Small amounts of cobalt compounds are found in most rocks, soils, plants, and animals.{{Citation |last=Domingo |first=Jose L. |title=Reviews of Environmental Contamination and Toxicology |chapter=Cobalt in the Environment and Its Toxicological Implications |date=1989 |chapter-url=https://doi.org/10.1007/978-1-4613-8850-0_3 |pages=105–132 |editor-last=Ware |editor-first=George W. |access-date=30 November 2023 |volume=108 |location=New York |publisher=Springer |language=en |doi=10.1007/978-1-4613-8850-0_3 |pmid=2646660 |isbn=978-1-4613-8850-0}} In the ocean cobalt typically reacts with chlorine.

In nature, cobalt is frequently associated with nickel. Both are characteristic components of meteoric iron, though cobalt is much less abundant in iron meteorites than nickel. As with nickel, cobalt in meteoric iron alloys may have been well enough protected from oxygen and moisture to remain as the free (but alloyed) metal.{{cite journal|url=http://rruff.info/rdsmi/V35/RDSMI35_355.pdf |title=Determination of metallic iron, nickel and cobalt in meteorites |author=Nuccio, Pasquale Mario |author2=Valenza, Mariano |year=1979 |journal=Rendiconti Societa Italiana di Mineralogia e Petrografia |volume=35 |issue=1 |pages=355–360}}

Cobalt in compound form occurs in copper and nickel minerals. It is the major metallic component that combines with sulfur and arsenic in the sulfidic cobaltite (CoAsS), safflorite (CoAs₂), glaucodot ({{chem|(Co|,Fe)|As|S}}), and skutterudite (CoAs₃) minerals. The mineral cattierite is similar to pyrite and occurs together with vaesite in the copper deposits of Katanga Province. When it reaches the atmosphere, weathering occurs; the sulfide minerals oxidize and form pink erythrite ("cobalt glance": Co₃(AsO₄)₂·8H₂O) and spherocobaltite (CoCO₃).{{cite journal|last1 =Buckley|first1 =A. N.|title =The Surface Oxidation of Cobaltite|journal =Australian Journal of Chemistry|volume =40|page =231|date =1987|doi =10.1071/CH9870231|issue =2}}{{cite journal|last1 =Young|first1 =R.|title =The geochemistry of cobalt|journal =Geochimica et Cosmochimica Acta|volume =13|issue =1|pages =28–41|date =1957|doi =10.1016/0016-7037(57)90056-X|bibcode = 1957GeCoA..13...28Y }}

Cobalt is also a constituent of tobacco smoke. The tobacco plant readily absorbs and accumulates heavy metals like cobalt from the surrounding soil in its leaves. These are subsequently inhaled during tobacco smoking.

File:Cobalt OreUSGOV.jpg

{{See also|Cobalt extraction}}

The main ores of cobalt are cobaltite, erythrite, glaucodot and skutterudite (see above), but most cobalt is obtained by reducing the cobalt by-products of nickel and copper mining and smelting.{{cite web|url = http://minerals.usgs.gov/minerals/pubs/commodity/cobalt/myb1-2006-cobal.pdf|first = Kim B.|last = Shedd|access-date = 26 October 2008|title = Mineral Yearbook 2006: Cobalt|publisher = United States Geological Survey}}{{cite web|url = http://minerals.usgs.gov/minerals/pubs/commodity/cobalt/mcs-2008-cobal.pdf|first = Kim B.|last = Shedd|access-date = 26 October 2008|title = Commodity Report 2008: Cobalt|publisher = United States Geological Survey}}

Since cobalt is generally produced as a by-product, the supply of cobalt depends to a great extent on the economic feasibility of copper and nickel mining in a given market. Demand for cobalt was projected to grow 6% in 2017.{{cite news|url=https://www.ft.com/content/bc8dc13c-07db-11e7-97d1-5e720a26771b|title=Cobalt's meteoric rise at risk from Congo's Katanga|author=Henry Sanderson |date=14 March 2017|work=Financial Times|location=London | url-access=limited}}

Primary cobalt deposits are rare, such as those occurring in hydrothermal deposits, associated with ultramafic rocks, typified by the Bou-Azzer district of Morocco. At such locations, cobalt ores are mined exclusively, albeit at a lower concentration, and thus require more downstream processing for cobalt extraction.Murray W. Hitzman, Arthur A. Bookstrom, John F. Slack, and Michael L. Zientek (2017). [https://pubs.usgs.gov/of/2017/1155/ofr20171155.pdf "Cobalt—Styles of Deposits and the Search for Primary Deposits"]. United States Geological Survey. Retrieved 17 April 2021.[https://www.mining.com/cobalt-price-bmw-avoids-the-congo-conundrum-for-now/ "Cobalt price: BMW avoids the Congo conundrum – for now"]. Mining.com. Retrieved 17 April 2021.

Several methods exist to separate cobalt from copper and nickel, depending on the concentration of cobalt and the exact composition of the used ore. One method is froth flotation, in which surfactants bind to ore components, leading to an enrichment of cobalt ores. Subsequent roasting converts the ores to cobalt sulfate, and the copper and the iron are oxidized to the oxide. Leaching with water extracts the sulfate together with the arsenates. The residues are further leached with sulfuric acid, yielding a solution of copper sulfate. Cobalt can also be leached from the slag of copper smelting.{{cite book|page = 347| title = ASM specialty handbook: nickel, cobalt, and their alloys| author =Davis, Joseph R.|publisher = ASM International| date = 2000| isbn = 0-87170-685-7| url = https://books.google.com/books?id=IePhmnbmRWkC&q=cobalt+copper+nickel+ore+separate}}

The products of the above-mentioned processes are transformed into the cobalt oxide (Co₃O₄). This oxide is reduced to metal by the aluminothermic reaction or reduction with carbon in a blast furnace.

File:Cobalt - world production trend.svg

{{see also|Cobalt extraction}}

File:World- Cobalt Production, 1944* - DPLA - c1037ee27d2f7452509d5cade20dc8b9.jpg

The United States Geological Survey estimates world reserves of cobalt at 7,100,000 metric tons.

{{cite web |url=https://minerals.usgs.gov/minerals/pubs/commodity/cobalt/mcs-2016-cobal.pdf

|title=Cobalt

|pages=52–53

|date=January 2016

|publisher=United States Geological Survey, Mineral Commodity Summaries

}}

The Democratic Republic of the Congo (DRC) currently produces 63% of the world's cobalt. This market share may reach 73% by 2025 if planned expansions by mining producers like Glencore Plc take place as expected. Bloomberg New Energy Finance has estimated that by 2030, global demand for cobalt could be 47 times more than it was in 2017.{{cite news |author=Wilson |first=Thomas |date=26 October 2017 |title=We'll All Be Relying on Congo to Power Our Electric Cars |publisher=Bloomberg News |url=https://www.bloomberg.com/news/articles/2017-10-26/battery-boom-relies-on-one-african-nation-avoiding-chaos-of-past |url-access=subscription |access-date=25 March 2023}}

{{See also|Mining industry of the Democratic Republic of the Congo}}

File:Artisanal cobalt miners in the Democratic Republic of Congo.jpg]]

Changes that Congo made to mining laws in 2002 attracted new investments in Congolese copper and cobalt projects. In 2005, the top producer of cobalt was the copper deposits in the Democratic Republic of the Congo's Katanga Province. Formerly Shaba province, the area had almost 40% of global reserves, reported the British Geological Survey in 2009.{{cite web

| url = http://www.bgs.ac.uk/mineralsuk/downloads/african_mp_01_05.pdf| title =African Mineral Production |publisher = British Geological Survey

|access-date = 6 June 2009}}

The Mukondo Mountain project, operated by the Central African Mining and Exploration Company (CAMEC) in Katanga Province, may be the richest cobalt reserve in the world. It produced an estimated one-third of the total global cobalt production in 2008. In July 2009, CAMEC announced a long-term agreement to deliver its entire annual production of cobalt concentrate from Mukondo Mountain to Zhejiang Galico Cobalt & Nickel Materials of China.{{cite web|url=http://www.miningweekly.com/article/daily-podcast---july-6-2009-2009-07-06-2 |title=Daily podcast – July 6, 2009 |author=Amy Witherden |date=6 July 2009 |work=Mining weekly |access-date=15 November 2011}}

In 2016, Chinese ownership of cobalt production in the Congo was estimated at over 10% of global cobalt supply, forming a key input to the Chinese cobalt refining industry and granting China substantial influence over the global cobalt supply chain.{{Cite journal |last1=Gulley |first1=Andrew |last2=McCullough |first2=Erin |last3=Shedd |first3=Kim |date=August 2019 |title=China's domestic and foreign influence in the global cobalt supply chain |journal=Resources Policy |volume=62 |pages=317–323 |doi=10.1016/j.resourpol.2019.03.015 |bibcode=2019RePol..62..317G |doi-access=free }} Chinese control of Congolese cobalt has raised concern in Western nations which have sought to reduce supply chain reliance upon China and have expressed concern regarding labor and human rights violations in cobalt mines in the DRC.{{Cite web |date=14 November 2023 |title=From Cobalt to Cars: How China Exploits Child and Forced Labor in the Congo {{!}} Congressional-Executive Commission on China |url=https://www.cecc.gov/events/hearings/from-cobalt-to-cars-how-china-exploits-child-and-forced-labor-in-the-congo |website=cecc.gov}}{{Cite news |last=Home |first=Andy |date=19 February 2024 |title=West challenges China's critical minerals hold on Africa |url=https://www.reuters.com/markets/commodities/west-challenges-chinas-critical-minerals-hold-africa-2024-02-16/ |agency=Reuters}}

Glencore's Mutanda Mine shipped 24,500 tons of cobalt in 2016, 40% of Congo DRC's output and nearly a quarter of global production. After oversupply, Glencore closed Mutanda for two years in late 2019.{{cite web |title=Glencore's cobalt stock overhang contains prices despite mine suspension |url=https://www.reuters.com/article/us-glencore-cobalt-prices/glencores-cobalt-stock-overhang-contains-prices-despite-mine-suspension-idUSKCN1UY1PU |agency=Reuters|language=en |date=8 August 2019}}{{cite web |title=Glencore closes Mutanda mine, 20% of global cobalt supply comes offline |url=https://www.benchmarkminerals.com/glencore-closes-mutanda-mine-20-of-global-cobalt-supply-comes-offline/ |publisher=Benchmark Mineral Intelligence |date=28 November 2019 |quote=the mine would be placed on care and maintenance for a period of no less than two years}} Glencore's Katanga Mining project is resuming as well and should produce 300,000 tons of copper and 20,000 tons of cobalt by 2019, according to Glencore.

In February 2018, global asset management firm AllianceBernstein defined the DRC as economically "the Saudi Arabia of the electric vehicle age", due to its cobalt resources, as essential to the lithium-ion batteries that drive electric vehicles.[https://www.mining-journal.com/capital-markets/news/1311386/-ivanhoe-pullback-investors-waiting Mining Journal] "The [Ivanhoe] pullback investors have been waiting for", Aspermont Ltd., London, UK, 22 February 2018. Retrieved 21 November 2018.

On 9 March 2018, President Joseph Kabila updated the 2002 mining code, increasing royalty charges and declaring cobalt and coltan "strategic metals".[https://www.reuters.com/article/us-congo-mining-cobalt/cobalt-to-be-declared-a-strategic-mineral-in-congo-idUSKCN1GQ2RX Shabalala, Zandi] "Cobalt to be declared a strategic mineral in Congo", Reuters, 14 March 2018. Retrieved 3 October 2018.Reuters, "[https://www.reuters.com/article/us-congo-mining/congos-kabila-signs-into-law-new-mining-code-idUSKCN1GL2MB Congo's Kabila signs into law new mining code]", 14 March 2018. Retrieved 3 October 2018. The 2002 mining code was effectively updated on 4 December 2018.[https://www.mining-journal.com/politics/news/1352362/drc-declares-cobalt-%E2%80%98strategic%E2%80%99 "DRC declares cobalt 'strategic{{'"}}], Mining Journal, 4 December 2018. Retrieved 7 October 2020.

In February 2025, the DRC implemented a four-month suspension of cobalt exports, citing an oversupply of the metal amid a price decline to its lowest level in 21 years. Cobalt, a key byproduct of copper mining, is an essential material in battery technology. The DRC accounts for approximately 75 percent of the global supply. Within the country, the China Molybdenum Company (CMOC) dominates the industry, contributing roughly 40 percent of the world's cobalt production. Over the past year, CMOC has significantly increased its output, doubling production from two of its mines in the DRC from 56,000 tonnes to 114,000 tonnes.

{{See also|Conflict minerals}}

Artisanal mining supplied 17% to 40% of the DRC production as of 2016. Some 100,000 cobalt miners in Congo DRC use hand tools to dig hundreds of feet, with little planning and fewer safety measures, say workers and government and NGO officials, as well as The Washington Post reporters' observations on visits to isolated mines. The lack of safety precautions frequently causes injuries or death.{{Cite news|url=https://www.washingtonpost.com/news/in-sight/wp/2018/02/28/the-cost-of-cobalt/|title=Perspective – The hidden costs of cobalt mining|last1=Mucha|first1=Lena|date=28 February 2018|newspaper=The Washington Post |access-date=7 March 2018|last2=Sadof|first2=Karly Domb|language=en-US|issn=0190-8286|last3=Frankel|first3=Todd C.}} Mining pollutes the vicinity and exposes local wildlife and indigenous communities to toxic metals thought to cause birth defects and breathing difficulties, according to health officials.{{cite news |title=The Cobalt Pipeline: Tracing the path from deadly hand-dug mines in Congo to consumers' phones and laptops |last=Frankel |first=Todd C. |author-link= |newspaper=The Washington Post |date=30 September 2016 |url=https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/}}

Child labor is used in mining cobalt from African artisanal mines.{{cite news|url= https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/ |title=Cobalt mining for lithium ion batteries has a high human cost |first=Todd C. |last=Frankel |author-link= |date=30 September 2016 |newspaper=The Washington Post|access-date= 18 October 2016}}{{cite web |url=https://www.amnesty.org/en/latest/news/2016/01/child-labour-behind-smart-phone-and-electric-car-batteries/ |title=Child labour behind smart phone and electric car batteries |publisher=Amnesty International |date=19 January 2016 |access-date=7 January 2018}} Human rights activists have highlighted this and investigative journalism reporting has confirmed it.{{cite web |last=Crawford |first=Alex |url=http://news.sky.com/story/meet-dorsen-8-who-mines-cobalt-to-make-your-smartphone-work-10784120 |title=Meet Dorsen, 8, who mines cobalt to make your smartphone work |work=Sky News |access-date=7 January 2018}}{{cite web |url=http://news.sky.com/video/are-you-holding-a-product-of-child-labour-right-now-10785338 |title=Are you holding a product of child labour right now? (Video) |work=Sky News |date=28 February 2017 |access-date=7 January 2018}} This revelation prompted cell phone maker Apple Inc., on 3 March 2017, to stop buying ore from suppliers such as Zhejiang Huayou Cobalt who source from artisanal mines in the DRC, and begin using only suppliers that are verified to meet its workplace standards.

{{cite web |last=Reisinger |first=Don |date=3 March 2017 |url=http://fortune.com/2017/03/03/apple-cobalt-child-labor/ |title=Child Labor Revelation Prompts Apple to Make Supplier Policy Change |work=Fortune |access-date=7 January 2018}}{{cite web |last=Frankel |first=Todd C. |date=3 March 2017 |url=https://www.washingtonpost.com/news/the-switch/wp/2017/03/03/apple-cracks-down-further-on-cobalt-supplier-in-congo-as-child-labor-persists/ |title=Apple cracks down further on cobalt supplier in Congo as child labor persists |work=The Washington Post |access-date=7 January 2018}} In 2023, Apple announced it would convert to using recycled cobalt by 2025.{{Cite web| year=2023 | title=Apple to use only recycled cobalt in batteries by 2025 |work=Reuters | url=https://www.reuters.com/technology/apple-use-100-recycled-cobalt-batteries-by-2025-2023-04-13/ | access-date=9 November 2024}}

There is a push globally by the EU and major car manufacturers (OEM) for global production of cobalt to be sourced and –produced sustainably, responsibly and traceability of the supply chain. Mining companies are adopting and practising ESG initiatives in line with OECD Guidance and putting in place evidence of zero to low carbon footprint activities in the supply chain production of lithium-ion batteries. These initiatives are already taking place with major mining companies, artisanal and small-scale mining companies (ASM). Car manufacturers and battery manufacturer supply chains: Tesla, VW, BMW, BASF and Glencore are participating in several initiatives, such as the Responsible Cobalt Initiative{{Cite web |title=Responsible Cobalt Initiative (RCI) |url=https://respect.international/responsible-cobalt-initiative-rci/ |access-date=28 November 2024 |website=respect.international |language=en-GB}} and Cobalt for Development{{Cite web |last=Development |first=Cobalt for |title=Cobalt for Development (C4D) - Towards responsible artisanal cobalt mining in the DR Congo |url=https://cobalt4development.com/ |access-date=28 November 2024 |website=Cobalt for Development (C4D) |language=English}} study. In 2018 BMW Group in partnership with BASF, Samsung SDI and Samsung Electronics have launched a pilot project in the DRC over one pilot mine, to improve conditions and address challenges for artisanal miners and the surrounding communities.

The political and ethnic dynamics of the region have in the past caused outbreaks of violence and years of armed conflict and displaced populations. This instability affected the price of cobalt and also created perverse incentives for the combatants in the First and Second Congo Wars to prolong the fighting, since access to diamond mines and other valuable resources helped to finance their military goals—which frequently amounted to genocide—and also enriched the fighters themselves. While DR Congo has in the 2010s not recently been invaded by neighboring military forces, some of the richest mineral deposits adjoin areas where Tutsis and Hutus still frequently clash, unrest continues although on a smaller scale and refugees still flee outbreaks of violence.{{cite web|url = http://pubs.usgs.gov/circ/2007/1294/paper1.html |title = Global Nonfuel Mineral Resources and Sustainability |last1=Wellmer |first1=Friedrich-Wilhelm |author1-link= |last2=Becker-Platen |first2=Jens Dieter |author2= |access-date = 16 May 2009}}

Cobalt extracted from small Congolese artisanal mining endeavors in 2007 supplied a single Chinese company, Congo DongFang International Mining. A subsidiary of Zhejiang Huayou Cobalt, one of the world's largest cobalt producers, Congo DongFang supplied cobalt to some of the world's largest battery manufacturers, who produced batteries for ubiquitous products like the Apple iPhones. Because of accused labour violations and environmental concerns, LG Chem subsequently audited Congo DongFang in accordance with OECD guidelines. LG Chem, which also produces battery materials for car companies, imposed a code of conduct on all suppliers that it inspects.[https://www.lgchem.com/asset/doc/Audit_Report_CDM_2018.pdf Audit Report on Congo Dongfang International Mining sarl]. DNV-GL Retrieved 18 April 2021.

In December 2019, International Rights Advocates, a human rights NGO, filed a landmark lawsuit against Apple, Tesla, Dell, Microsoft and Google company Alphabet for "knowingly benefiting from and aiding and abetting the cruel and brutal use of young children" in mining cobalt.{{Cite web|date=17 December 2019|title=U.S. cobalt lawsuit puts spotlight on 'sustainable' tech|url=https://www.sustainability-times.com/sustainable-business/u-s-cobalt-lawsuit-puts-spotlight-on-sustainable-tech/|access-date=16 September 2020|website=Sustainability Times|language=en-GB}} The companies in question denied their involvement in child labour.{{Cite web|title=Apple, Google Fight Blame For Child Labor in Cobalt Mines – Law360|url=https://www.law360.com/articles/1304511/apple-google-fight-blame-for-child-labor-in-cobalt-mines|access-date=16 September 2020|website=law360.com|language=en}} In 2024 the court ruled that the suppliers facilitate force labor but the US tech companies are not liable because they don't operate as a shared enterprise with the suppliers and that the "alleged injuries are not fairly traceable" to any of the defendants' conduct.{{Cite web|date=6 March 2024|title=Buying cobalt doesn't make US firms liable for abuses in DR Congo | url=https://arstechnica.com/tech-policy/2024/03/apple-and-other-firms-dont-have-to-compensate-victims-of-forced-child-labor/ }} The book Cobalt Red{{Cite book |last=Kara |first=Siddharth |title=Cobalt red: how the blood of the Congo powers our lives |date=2023 |publisher=St. Martin's Press |isbn=978-1-250-28429-7 |edition=First |location=New York, New York}}{{Cite web |last=Aikins |first=Matthieu |title=How Is Your Phone Powered? Problematically. |url=https://www.nytimes.com/2023/01/23/books/review/cobalt-red-siddharth-kara.html |access-date=9 November 2024 |website=The New York Times |quote=Siddharth Kara’s "Cobalt Red" takes a deep dive into the horrors of mining the valuable mineral – and the many who benefit from others' suffering.}} alleges that workers including children suffer injuries, amputations, and death as the result of the hazardous working conditions and mine tunnel collapses during artisanal mining of cobalt in the DRC.{{cite web |url=https://www.npr.org/sections/goatsandsoda/2023/02/01/1152893248/red-cobalt-congo-drc-mining-siddharth-kara |title=How 'modern-day slavery' in the Congo powers the rechargeable battery economy |work=NPR |last=Gross |first=Terry |date=1 February 2023 |access-date=31 March 2025}}

Since child and slave labor have been repeatedly reported in cobalt mining, primarily in the artisanal mines of DR Congo, technology companies seeking an ethical supply chain have faced shortages of this raw material and{{cite web |last=Hermes |first=Jennifer |date=31 May 2017 |url=https://www.environmentalleader.com/2017/05/shortage-ethically-sourced-cobalt-congo-causes-trouble-ge-apple-tesla/ |title=Tesla & GE Face Major Shortage Of Ethically Sourced Cobalt |archive-url=https://web.archive.org/web/20190402084909/https://www.environmentalleader.com/2017/05/shortage-ethically-sourced-cobalt-congo-causes-trouble-ge-apple-tesla/ |archive-date=2 April 2019 |website=Environmentalleader.com |access-date=7 January 2018}} the price of cobalt metal reached a nine-year high in October 2017, more than US$30 a pound, versus US$10 in late 2015.{{cite web |url=http://www.mining.com/web/electric-cars-yet-turn-cobalt-market-gold-mine-nornickel/ |title=Electric cars yet to turn cobalt market into gold mine – Nornickel |website=Mining.com |date=30 October 2017 |access-date=7 January 2018}} After oversupply, the price dropped to a more normal $15 in 2019.{{cite web |title=Why Have Cobalt Prices Crashed |url=https://internationalbanker.com/brokerage/why-have-cobalt-prices-crashed/ |website=International Banker |date=31 July 2019 |archive-url=https://web.archive.org/web/20191130150758/https://internationalbanker.com/brokerage/why-have-cobalt-prices-crashed/ |archive-date=30 November 2019 |url-status=live}}{{cite web |title=Cobalt Prices and Cobalt Price Charts – InvestmentMine |url=http://www.infomine.com/investment/metal-prices/cobalt/ |website=infomine.com}} As a reaction to the issues with artisanal cobalt mining in DR Congo a number of cobalt suppliers and their customers have formed the Fair Cobalt Alliance (FCA) which aims to end the use of child labor and to improve the working conditions of cobalt mining and processing in the DR Congo. Members of FCA include Zhejiang Huayou Cobalt, Sono Motors, the Responsible Cobalt Initiative, Fairphone, Glencore and Tesla, Inc.{{cite news|url= https://www.mining-technology.com/news/tesla-joins-fair-cobalt-alliance/ |website= mining-technology.com |title= Tesla joins "Fair Cobalt Alliance" to improve DRC artisanal mining |date= 8 September 2020 |access-date= 26 September 2020}}{{cite news|url= https://www.teslarati.com/tesla-fair-cobalt-alliance-mining/ |website= teslarati.com |title= Tesla joins Fair Cobalt Alliance in support of moral mining efforts |first= Joey |last= Klender |date= 8 September 2020 |access-date= 26 September 2020}}

In 2017, some exploration companies were planning to survey old silver and cobalt mines in the area of Cobalt, Ontario, where significant deposits are believed to lie.{{Cite web |title=The Canadian Ghost Town That Tesla Is Bringing Back to Life |url=https://www.bloomberg.com/news/features/2017-10-31/the-canadian-ghost-town-that-tesla-is-bringing-back-to-life |archive-url=http://web.archive.org/web/20240502164439/https://www.bloomberg.com/news/features/2017-10-31/the-canadian-ghost-town-that-tesla-is-bringing-back-to-life |archive-date=2024-05-02 |access-date=2025-04-18 |website=Bloomberg.com |language=en}}

Cobalt mined in Canada is a by-product of nickel mining. Even so, in 2023 the country produced more than 5,000 tons of cobalt (43% is mined in Newfoundland and Labrador, the rest in Ontario, Manitoba and Quebec). Exports of cobalt and cobalt products totaled $568 million in 2023.{{Cite web |last=Canada |first=Natural Resources |date=2023-03-09 |title=Cobalt facts |url=https://natural-resources.canada.ca/minerals-mining/mining-data-statistics-analysis/minerals-metals-facts/cobalt-facts |access-date=2025-04-18 |website=natural-resources.canada.ca}}

Canada's Sherritt International processes cobalt ores in nickel deposits from the Moa mines in Cuba, and the island has several others mines in Mayarí, Camagüey, and Pinar del Río. Continued investments by Sherritt International in Cuban nickel and cobalt production while acquiring mining rights for 17–20 years made the communist country third for cobalt reserves in 2019, before Canada itself.[https://www.cubabusinessreport.com/cubas-nickel-production-exceeds-50000-metric-tons/ "Cubas Nickel Production Exceeds 50000 metric tons]". Cuba Business Report. Retrieved 18 April 2021.

Starting from smaller amounts in 2021, Indonesia began producing cobalt as a byproduct of nickel production. By 2022, the country had become the world's second-largest cobalt producer, with Benchmark Mineral Intelligence forecasting Indonesian output to make up 20 percent of global production by 2030.{{cite news |title=The biggest source of cobalt outside Africa is now Indonesia |url=https://www.mining.com/web/the-biggest-source-of-cobalt-outside-africa-is-now-indonesia/ |access-date=10 May 2023 |publisher=Bloomberg News |date=8 February 2023}} Cobalt production increased from 1,300 tons to 20,500 tons between 2015 and 2024 due to the Indonesian government's strategic initiative to develop a robust domestic supply chain for electric vehicles. An export ban in 2020 has ensured an influx of foreign investment in nickel and cobalt processing in the country.{{Cite web |last=GlobalData |date=2025-01-17 |title=Global cobalt supply to surpass 300kt mark in 2024, driven by production from the DRC and Indonesia |url=https://www.mining-technology.com/analyst-comment/global-cobalt-supply-2024/ |access-date=2025-04-20 |website=Mining Technology |language=en-US}}

In 2016, {{convert|116000|t|ST}} of cobalt was used. Cobalt has been used in the production of high-performance alloys. It is also used in some rechargeable batteries.

Cobalt-based superalloys have historically consumed most of the cobalt produced. The temperature stability of these alloys makes them suitable for turbine blades for gas turbines and aircraft jet engines, although nickel-based single-crystal alloys surpass them in performance. Cobalt-based alloys are also corrosion- and wear-resistant, making them, like titanium, useful for making orthopedic implants that do not wear down over time. The development of wear-resistant cobalt alloys started in the first decade of the 20th century with the stellite alloys, containing chromium with varying quantities of tungsten and carbon. Alloys with chromium and tungsten carbides are very hard and wear-resistant.{{cite book |chapter-url = https://books.google.com/books?id=6VdROgeQ5M8C&pg=PA557 |isbn = 978-0-87170-867-0|chapter = Cobalt and Cobalt Alloys |pages = 557–558 |title = Elements of metallurgy and engineering alloys |author1 = Campbell, Flake C |date = 30 June 2008| publisher=ASM International }} Special cobalt-chromium-molybdenum alloys like Vitallium are used for prosthetic parts (hip and knee replacements).{{cite journal |title = Systemic effects of implanted prostheses made of cobalt-chromium alloys |journal = Archives of Orthopaedic and Trauma Surgery |volume = 110 |issue = 2 |date = 1991 |doi = 10.1007/BF00393876 |pages = 61–74 |first = R. |last = Michel |author2 = Nolte, M. |author3 = Reich M. |author4 = Löer, F. |pmid = 2015136|s2cid = 28903564 }} Cobalt alloys are also used for dental prosthetics as a useful substitute for nickel, which may be allergenic.{{cite book |title = Cobalt-base Aloys for Biomedical Applications |first = John A. |last = Disegi |publisher = ASTM International |date = 1999 |isbn = 0-8031-2608-5 |url = https://books.google.com/books?id=z4rXM1EnPugC |page=34}} Some high-speed steels also contain cobalt for increased heat and wear resistance. The special alloys of aluminium, nickel, cobalt and iron, known as Alnico, and of samarium and cobalt (samarium–cobalt magnet) are used in permanent magnets.{{cite journal |title = Reproducing the Properties of Alnico Permanent Magnet Alloys with Elongated Single-Domain Cobalt-Iron Particles |journal = Journal of Applied Physics |volume = 28 |issue = 344 |date = 1957 |doi = 10.1063/1.1722744 |first = F. E. |last = Luborsky |author2 = Mendelsohn, L. I. |author3 = Paine, T. O. |page = 344 |bibcode = 1957JAP....28..344L }} It is also alloyed with 95% platinum for jewelry, yielding an alloy suitable for fine casting, which is also slightly magnetic.{{cite journal |doi = 10.1595/147106705X24409 |title = The Hardening of Platinum Alloys for Potential Jewellery Application |date = 2005 |last1 = Biggs |first1 = T. |last2 = Taylor |first2 = S. S. |last3 = Van Der Lingen |first3 = E. |journal = Platinum Metals Review |volume = 49 |pages = 2–15|doi-access = free }}

Lithium cobalt oxide (LiCoO₂, aka "LCO"), first sold commercially in 1991 by Sony, was widely used in lithium-ion battery cathodes until the 2010s. The material is composed of cobalt oxide layers with the lithium intercalated. These LCO batteries continue to dominate the market for consumer electronics. Batteries for electric cars however have shifted to lower cobalt technologies.{{Cite journal |last=Frith |first=James T. |last2=Lacey |first2=Matthew J. |last3=Ulissi |first3=Ulderico |date=26 January 2023 |title=A non-academic perspective on the future of lithium-based batteries |url=https://www.nature.com/articles/s41467-023-35933-2 |journal=Nature Communications |language=en |volume=14 |issue=1 |pages=420 |doi=10.1038/s41467-023-35933-2 |issn=2041-1723 |pmc=9879955 |pmid=36702830}}

In 2018 most cobalt in batteries was used in a mobile device,{{cite web | last1 = Castellano | first1 = Robert | date = 13 October 2017 | url = https://seekingalpha.com/article/4113417-minimize-teslas-cobalt-supply-chain-risk | title = How To Minimize Tesla's Cobalt Supply Chain Risk | work = Seeking Alpha | archive-url = https://web.archive.org/web/20220404152632/https://seekingalpha.com/article/4113417-how-to-minimize-teslas-cobalt-supply-chain-risk | archive-date = 4 April 2022 | url-status = live | access-date = 29 June 2022}} a more recent application for cobalt is rechargeable batteries for electric cars. This industry increased five-fold in its demand for cobalt from 2016 to 2020, which made it urgent to find new raw materials in more stable areas of the world.{{cite news|url= https://cleantechnica.com/2017/11/28/cobalt-supply-tightens-lico-energy-metals-announces-two-new-cobalt-mines/ |website= cleantechnica.com |title= As Cobalt Supply Tightens, LiCo Energy Metals Announces Two New Cobalt Mines |date= 28 November 2017 |access-date= 7 January 2018}} Demand is expected to continue or increase as the prevalence of electric vehicles increases.{{cite web | last1 = Shilling | first1 = Erik | date = 31 October 2017 | url = https://jalopnik.com/we-may-not-have-enough-minerals-to-even-meet-electric-c-1820008337 | title = We May Not Have Enough Minerals To Even Meet Electric Car Demand | work = Jalopnik | archive-url = https://web.archive.org/web/20220401011155/https://jalopnik.com/we-may-not-have-enough-minerals-to-even-meet-electric-c-1820008337 | archive-date = 1 April 2022 | url-status = live | access-date = 29 June 2022 }} Exploration in 2016–2017 included the area around Cobalt, Ontario, an area where many silver mines ceased operation decades ago. Cobalt for electric vehicles increased 81% from the first half of 2018 to 7,200 tonnes in the first half of 2019, for a battery capacity of 46.3 GWh.{{cite web |title=State of Charge: EVs, Batteries and Battery Materials (Free Report from @AdamasIntel) |url=https://www.adamasintel.com/state-of-charge-2019-h1/ |website=Adamas Intelligence |date=20 September 2019 |access-date=20 October 2019 |archive-date=20 October 2019 |archive-url=https://web.archive.org/web/20191020195558/https://www.adamasintel.com/state-of-charge-2019-h1/ }}{{cite web |title=Muskmobiles running rivals off the road |url=https://www.mining.com/muskmobiles-running-rivals-off-the-road/ |website=MINING.COM |archive-url= https://web.archive.org/web/20190930213809/https://www.mining.com/muskmobiles-running-rivals-off-the-road/ |archive-date=30 September 2019 |date=26 September 2019 |url-status=live}}

As of August 2020 battery makers have gradually reduced the cathode cobalt content from 1/3 (NMC 111) to 1/5 (NMC 442) to currently 1/10 (NMC 811) and have also introduced the cobalt free lithium iron phosphate cathode into the battery packs of electric cars such as the Tesla Model 3.{{cite news|url= https://www.koreatimes.co.kr/www/tech/2020/08/419_294410.html |website= The Korea Times |title= Tesla's battery strategy, implications for LG and Samsung |first= Kim |last= Yoo-chul |date= 14 August 2020 |access-date= 26 September 2020}}{{cite news|url= https://cleantechnica.com/2020/08/31/lithium-nickel-tesla-oh-my/ |website= cleantechnica.com |title= Lithium & Nickel & Tesla, Oh My! |first= Zachary |last= Shahan |date= 31 August 2020 |access-date= 26 September 2020}}

Research was also conducted by the European Union into the possibility of eliminating cobalt requirements in lithium-ion battery production.[https://projectcobra.eu/#cobra CObalt-free Batteries for FutuRe Automotive Applications website][https://cordis.europa.eu/project/id/875568 COBRA project at European Union]

In September 2020, Tesla outlined their plans to make their own, cobalt-free battery cells.{{cite news|url= https://www.theverge.com/2020/9/22/21451670/tesla-cobalt-free-cathodes-mining-battery-nickel-ev-cost |website= theverge.com |title= Tesla to make EV battery cathodes without cobalt |first= Justine |last= Calma |date= 22 September 2020 |access-date= 26 September 2020}}

Nickel–cadmium (NiCd) and nickel metal hydride (NiMH) batteries also included cobalt to improve the oxidation of nickel in the battery.

Lithium iron phosphate batteries officially surpassed ternary cobalt batteries in 2021 with 52% of installed capacity. Analysts estimate that its market share will exceed 60% in 2024.{{Cite web|url= https://m.energytrend.com/news/20220520-28100.html|title= EV Lithium Iron Phosphate Battery Battles Back |date= 25 May 2022|website=energytrend.com}}

Several cobalt compounds are oxidation catalysts. Cobalt acetate is used to convert xylene to terephthalic acid, the precursor of the bulk polymer polyethylene terephthalate. Typical catalysts are the cobalt carboxylates (known as cobalt soaps). They are also used in paints, varnishes, and inks as "drying agents" through the oxidation of drying oils.{{Cite web|title=Cobalt Drier for Paints {{!}} Cobalt Cem-All®|url=https://www.borchers.com/product/12-cobalt-cem-all/|access-date=15 May 2021|website=Borchers|language=en-US|archive-date=9 July 2023|archive-url=https://web.archive.org/web/20230709172932/https://www.borchers.com/product/12-cobalt-cem-all/|url-status=dead}} However, their use is being phased out due to toxicity concerns.{{Cite journal |last=Halstead |first=Joshua |date=April 2023 |title=Expanded Applications and Enhanced Durability of Alkyd Coatings Using High-Performance Catalysts |url=https://www.coatingstech-digital.org/coatingstech/library/item/may-june_2023/4096855/ |journal=CoatingsTech |volume=20 |issue=3 |pages=45–55 |publisher=American Coatings Association}} The same carboxylates are used to improve the adhesion between steel and rubber in steel-belted radial tires. In addition they are used as accelerators in polyester resin systems.{{Citation|last=Weatherhead|first=R. G.|title=Catalysts, Accelerators and Inhibitors for Unsaturated Polyester Resins|date=1980|work=FRP Technology: Fibre Reinforced Resin Systems|pages=204–239|editor-last=Weatherhead|editor-first=R. G.|location=Dordrecht|publisher=Springer Netherlands|language=en|doi=10.1007/978-94-009-8721-0_10|isbn=978-94-009-8721-0}}{{Cite web|title=The product selector {{!}} AOC|url=https://aocresins.com/en-amr/products/|access-date=15 May 2021|website=aocresins.com|language=en}}{{Cite web|title=Comar Chemicals – Polyester Acceleration|url=https://www.comarchemicals.com/index.php/en/products-en/other-organometallics-en/polyester-acceleration-en#:~:text=Cobalt%20is%20used%20to%20accelerate,customers%5C%5C%5C%27%20needs.|access-date=15 May 2021|website=comarchemicals.com|archive-date=15 May 2021|archive-url=https://web.archive.org/web/20210515152319/https://www.comarchemicals.com/index.php/en/products-en/other-organometallics-en/polyester-acceleration-en#:~:text=Cobalt%20is%20used%20to%20accelerate,customers%5C%5C%5C%27%20needs.}}

Cobalt-based catalysts are used in reactions involving carbon monoxide. Cobalt is also a catalyst in the Fischer–Tropsch process for the hydrogenation of carbon monoxide into liquid fuels. Hydroformylation of alkenes often uses cobalt octacarbonyl as a catalyst. The hydrodesulfurization of petroleum uses a catalyst derived from cobalt and molybdenum. This process helps to clean petroleum of sulfur impurities that interfere with the refining of liquid fuels.

File:bristol.blue.glass.arp.750pix.jpg

File:Cobalt blue flask.jpg

Before the 19th century, cobalt was predominantly used as a pigment. It has been used since the Middle Ages to make smalt, a blue-colored glass. Smalt is produced by melting a mixture of roasted mineral smaltite, quartz and potassium carbonate, which yields a dark blue silicate glass, which is finely ground after the production. Smalt was widely used to color glass and as pigment for paintings. In 1780, Sven Rinman discovered cobalt green, and in 1802 Louis Jacques Thénard discovered cobalt blue. Cobalt pigments such as cobalt blue (cobalt aluminate), cerulean blue (cobalt(II) stannate), various hues of cobalt green (a mixture of cobalt(II) oxide and zinc oxide), and cobalt violet (cobalt phosphate) are used as artist's pigments because of their superior chromatic stability.

Cobalt-60 (Co-60 or ⁶⁰Co) is useful as a gamma-ray source because it can be produced in predictable amounts with high activity by bombarding cobalt with neutrons. It produces gamma rays with energies of 1.17 and 1.33 MeV.

Cobalt is used in external beam radiotherapy, sterilization of medical supplies and medical waste, radiation treatment of foods for sterilization (cold pasteurization), industrial radiography (e.g. weld integrity radiographs), density measurements (e.g. concrete density measurements), and tank fill height switches. The metal has the unfortunate property of producing a fine dust, causing problems with radiation protection. Cobalt from radiotherapy machines has been a serious hazard when not discarded properly, and one of the worst radiation contamination accidents in North America occurred in 1984, when a discarded radiotherapy unit containing cobalt-60 was mistakenly disassembled in a junkyard in Juarez, Mexico.{{cite news |url=https://query.nytimes.com/gst/fullpage.html?sec=health&res=9501E7D71338F932A35756C0A962948260 |title=The Juarez accident |access-date=6 June 2009 |work =The New York Times |first=Sandra |last=Blakeslee |date=1 May 1984}}{{cite web | url=http://www.johnstonsarchive.net/nuclear/radevents/1983MEX1.html |title=Ciudad Juarez orphaned source dispersal, 1983 |date=23 November 2005 |access-date=24 October 2009 |publisher=Wm. Robert Johnston}}

Cobalt-60 has a radioactive half-life of 5.27 years. Loss of potency requires periodic replacement of the source in radiotherapy and is one reason why cobalt machines have been largely replaced by linear accelerators in modern radiation therapy.{{cite book |author1=National Research Council (U.S.). Committee on Radiation Source Use and Replacement |author2=National Research Council (U.S.). Nuclear and Radiation Studies Board |title=Radiation source use and replacement: abbreviated version |url=https://books.google.com/books?id=3cT2REdXJ98C&pg=PA35 |access-date=29 April 2011 |date=January 2008 |publisher=National Academies Press |isbn=978-0-309-11014-3 |pages=35–

}} Cobalt-57 (Co-57 or ⁵⁷Co) is a cobalt radioisotope most often used in medical tests, as a radiolabel for vitamin B{{ssub|12}} uptake, and for the Schilling test. Cobalt-57 is used as a source in Mössbauer spectroscopy and is one of several possible sources in X-ray fluorescence devices.

Nuclear weapon designs could intentionally incorporate ⁵⁹Co, some of which would be activated in a nuclear explosion to produce ⁶⁰Co. The ⁶⁰Co, dispersed as nuclear fallout, is sometimes called a cobalt bomb.

Due to the ferromagnetic properties of cobalt, it is used in the production of various magnetic materials.{{cite web |url=https://www.samaterials.com/content/what-is-cobalt-used-in-everyday-life.html |title=What is Cobalt Used in Everyday Life |last=Trento |first=Chin |website=Stanford Advanced Materials |date=14 April 2024 |access-date=24 June 2024}} It is used in creating permanent magnets like Alnico magnets, known for their strong magnetic properties used in electric motors, sensors, and MRI machines.{{cite book |title=Modern Permanent Magnets |publisher=Woodhead Publishing |editor-last1=Croat |editor-first1=John |editor-last2=Ormerod |editor-first2=John |pages=371–402 |date=2022 |chapter=Chapter 11:Permanent magnet coatings and testing procedures |series=Woodhead Publishing Series in Electronic and Optical Materials |doi=10.1016/B978-0-323-88658-1.00011-X |chapter-url=https://www.sciencedirect.com/science/article/abs/pii/B978032388658100011X |isbn=9780323886581 |access-date=24 June 2024}}{{cite web |url=https://radialmagnet.com/alnico-magnets-a-closer-look-at-their-history-properties-and-applications/ |title=Alnico Magnets: A Closer Look at Their History, Properties, and Applications |website=Radial Magnet|date=15 February 2024 |access-date=24 June 2024}} It is also used in production of magnetic alloys like cobalt steel, widely used in magnetic recording media such as hard disks and tapes.{{cite journal |last1=Mohapatra |first1=Jeotikanta |last2=Xing |first2=Meiying |date=2020 |title=Hard and semi-hard magnetic materials based on cobalt and cobalt alloys |journal=Journal of Alloys and Compounds |volume=824 |doi=10.1016/j.jallcom.2020.153874}}

Cobalt's ability to maintain magnetic properties at high temperatures makes it valuable in magnetic recording applications, ensuring reliable data storage devices.{{cite journal |last1=Yousuf |first1=Rehab |last2=Mahmoud |first2=Naglaa |date=2021 |title=Electric and magnetic properties of cobalt, copper and nickel organometallic complexes for molecular wires |journal=Ain Shams Engineering Journal |volume=12 |issue=2 |pages=2135–2144 |doi=10.1016/j.asej.2020.12.002|doi-access=free }} Cobalt also contributes to specialized magnets such as samarium-cobalt and neodymium-iron-boron magnets, which are vital in electronics for components like sensors and actuators.{{cite web |url=https://idealmagnetsolutions.com/knowledge-base/samarium-cobalt-vs-neodymium-magnets/ |title=Samarium Cobalt vs Neodymium Magnets |website=Ideal Magnet Solutions |date=15 May 2019 |access-date=24 June 2024}}

• Cobalt is used in electroplating for its attractive appearance, hardness, and resistance to oxidation.{{cite book|chapter-url = https://books.google.com/books?id=IePhmnbmRWkC&pg=PA354|author1 = Davis, Joseph R|title = Nickel, cobalt, and their alloys|page = 354|author2 = Handbook Committee, ASM International|date = 1 May 2000|chapter = Cobalt| publisher=ASM International |isbn = 978-0-87170-685-0}}
• It is also used as a base primer coat for porcelain enamels.{{cite book|chapter-url =https://books.google.com/books?id=-CIrAAAAYAAJ&pg=PA129| page = 129|chapter = Ground–Coat Frit|title =Cobalt conservation through technological alternatives|author1 =Committee on Technological Alternatives For Cobalt Conservation, National Research Council (U.S.)|author2 =National Materials Advisory Board, National Research Council (U.S.)|date =1983}}

Cobalt is essential to the metabolism of all animals. It is a key constituent of cobalamin, also known as vitamin B{{sub|12}}, the primary biological reservoir of cobalt as an ultratrace element. Bacteria in the stomachs of ruminant animals convert cobalt salts into vitamin B{{sub|12}}, a compound which can only be produced by bacteria or archaea. A minimal presence of cobalt in soils therefore markedly improves the health of grazing animals, and an uptake of 0.20 mg/kg a day is recommended, because they have no other source of vitamin B{{sub|12}}.{{cite journal |last1 = Schwarz |first1 = F. J. |last2 = Kirchgessner |first2 = M. |last3 = Stangl |first3 = G. I. |title = Cobalt requirement of beef cattle – feed intake and growth at different levels of cobalt supply |journal = Journal of Animal Physiology and Animal Nutrition |volume = 83 |pages = 121–131 |date = 2000 |doi = 10.1046/j.1439-0396.2000.00258.x |issue = 3}}

Proteins based on cobalamin use corrin to hold the cobalt. Coenzyme B₁₂ features a reactive C-Co bond that participates in the reactions.{{cite book |author=Voet, Judith G. |author2=Voet, Donald |title=Biochemistry |publisher=J. Wiley & Sons |location=New York |date=1995 |page=[https://archive.org/details/biochemistry00voet_0/page/675 675] |isbn=0-471-58651-X |oclc=31819701 |url-access=registration |url=https://archive.org/details/biochemistry00voet_0/page/675 }} In humans, B₁₂ has two types of alkyl ligand: methyl and adenosyl. MeB₁₂ promotes methyl (−CH₃) group transfers. The adenosyl version of B₁₂ catalyzes rearrangements in which a hydrogen atom is directly transferred between two adjacent atoms with concomitant exchange of the second substituent, X, which may be a carbon atom with substituents, an oxygen atom of an alcohol, or an amine. Methylmalonyl coenzyme A mutase (MUT) converts MMl-CoA to Su-CoA, an important step in the extraction of energy from proteins and fats.{{cite journal |last1 = Smith |first1 = David M. |last2 = Golding |first2 = Bernard T. |last3 = Radom |first3 = Leo |title = Understanding the Mechanism of B12-Dependent Methylmalonyl-CoA Mutase: Partial Proton Transfer in Action |journal = Journal of the American Chemical Society |volume = 121 |pages = 9388–9399 |date = 1999 |doi = 10.1021/ja991649a |issue = 40}}

Although far less common than other metalloproteins (e.g. those of zinc and iron), other cobaltoproteins are known besides B₁₂. These proteins include methionine aminopeptidase 2, an enzyme that occurs in humans and other mammals that does not use the corrin ring of B₁₂, but binds cobalt directly. Another non-corrin cobalt enzyme is nitrile hydratase, an enzyme in bacteria that metabolizes nitriles.{{cite journal |journal = European Journal of Biochemistry |volume = 261 |issue = 1 |pages =1–9 |title = Cobalt proteins |first = Michihiko |last = Kobayashi |author2=Shimizu, Sakayu |doi = 10.1046/j.1432-1327.1999.00186.x |date = 1999 |pmid = 10103026}}

In humans, consumption of cobalt-containing vitamin B₁₂ meets all needs for cobalt. For cattle and sheep, which meet vitamin B₁₂ needs via synthesis by resident bacteria in the rumen, there is a function for inorganic cobalt. In the early 20th century, during the development of farming on the North Island Volcanic Plateau of New Zealand, cattle suffered from what was termed "bush sickness". It was discovered that the volcanic soils lacked the cobalt salts essential for the cattle food chain.{{cite web |url=http://sci.waikato.ac.nz/farm/content/soils.html#bush_sickness |title=Soils |publisher=Waikato University |access-date=16 January 2012 |archive-url=https://web.archive.org/web/20120125213027/http://sci.waikato.ac.nz/farm/content/soils.html#bush_sickness |archive-date=25 January 2012 }}{{cite book |last1=McDowell |first1=Lee Russell |title=Vitamins in Animal and Human Nutrition |date=2008 |publisher=John Wiley & Sons |location=Hoboken |isbn=978-0-470-37668-3 |page=525 |edition=2nd |url=https://books.google.com/books?id=UR9MnQ806LsC&pg=PA525}} The "coast disease" of sheep in the Ninety Mile Desert of the Southeast of South Australia in the 1930s was found to originate in nutritional deficiencies of trace elements cobalt and copper. The cobalt deficiency was overcome by the development of "cobalt bullets", dense pellets of cobalt oxide mixed with clay given orally for lodging in the animal's rumen.{{clarify|date=March 2018}}[http://www.asap.unimelb.edu.au/bsparcs/aasmemoirs/marston.htm Australian Academy of Science > Deceased Fellows > Hedley Ralph Marston 1900–1965] Accessed 12 May 2013.{{cite journal | last= Snook | first = Laurence C. | year = 1962 | title = Cobalt: its use to control wasting disease | journal = Journal of the Department of Agriculture, Western Australia | series = 4 | volume = 3 | issue = 11 | pages = 844–852 | url = https://researchlibrary.agric.wa.gov.au/journal_agriculture4/vol3/iss11/2}}

File:Cobalamin.svg |alt=chemical diagram of cobalamin molecule|Cobalamin

File:CSIRO ScienceImage 10487 Cobalt deficient sheep.jpg |alt=two cobalt-deficient sheep facing away from camera|Cobalt-deficient sheep

{{Main|Cobalt poisoning}}

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The LD₅₀ value for soluble cobalt salts has been estimated to be between 150 and 500 mg/kg.Donaldson, John D. and Beyersmann, Detmar (2005) "Cobalt and Cobalt Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a07_281.pub2}} In the US, the Occupational Safety and Health Administration (OSHA) has designated a permissible exposure limit (PEL) in the workplace as a time-weighted average (TWA) of 0.1 mg/m³. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.05 mg/m³, time-weighted average. The IDLH (immediately dangerous to life and health) value is 20 mg/m³.{{PGCH|0146}}

However, chronic cobalt ingestion has caused serious health problems at doses far less than the lethal dose. In 1966, the addition of cobalt compounds to stabilize beer foam in Canada led to a peculiar form of toxin-induced cardiomyopathy, which came to be known as beer drinker's cardiomyopathy.{{cite journal |author= Morin Y |author2= Tětu A |author3= Mercier G|title=Quebec beer-drinkers' cardiomyopathy: Clinical and hemodynamic aspects |journal=Annals of the New York Academy of Sciences |volume=156 |issue= 1 |pages=566–576 |date=1969|pmid=5291148 |doi=10.1111/j.1749-6632.1969.tb16751.x|bibcode = 1969NYASA.156..566M |s2cid= 7422045 }}{{cite journal|title = Cobalt|author = Barceloux, Donald G.|author2 = Barceloux, Donald|name-list-style = amp |doi = 10.1081/CLT-100102420|pmid = 10382556|journal = Clinical Toxicology|volume = 37|issue = 2|date = 1999| pages = 201–216}}

Furthermore, cobalt metal is suspected of causing cancer (i.e., possibly carcinogenic, IARC Group 2B) as per the International Agency for Research on Cancer (IARC) Monographs.[http://publications.iarc.fr/_publications/media/download/2705/29aacee6b89ff816188dcd990b61a16ad6486eec.pdf [PDF]]

It causes respiratory problems when inhaled.{{cite news |last1=Elbagir |first1=Nima |last2=van Heerden |first2=Dominique |last3=Mackintosh |first3=Eliza |title=Dirty Energy |url=https://edition.cnn.com/interactive/2018/05/africa/congo-cobalt-dirty-energy-intl/ |access-date=30 May 2018 |publisher=CNN|date=May 2018}} It also causes skin problems when touched; after nickel and chromium, cobalt is a major cause of contact dermatitis.{{cite journal|journal = Contact Dermatitis|volume = 49|issue = 1|pages =1–7|doi = 10.1111/j.0105-1873.2003.00149.x|title = Nickel, chromium and cobalt in consumer products: revisiting safe levels in the new millennium|first =David A.|last = Basketter|author2 = Angelini, Gianni|author3 = Ingber, Arieh|author4 = Kern, Petra S.|author5 = Menné, Torkil|date = 2003|pmid = 14641113|s2cid = 24562378|doi-access = free}}

{{clear}}

{{Notelist}}

{{Reflist|refs=

{{cite book|last=Agricola |first=Georgius |author-link=Georgius Agricola |chapter=Bermannus, sive de re metallica dialogus |title=Georgii Agricolae De ortu & causis subterraneorum lib. 5. De natura eorum quae effluunt ex terra lib. 4. De natura fossilium lib. 10. De ueteribus & nouis metallis lib. 2. Bermannus, siue De re metallica dialogus lib.1. Interpretatio Germanica uocum rei metallicæ, addito Indice fœcundissimo |location=Basel |publisher=Froben |year=1546 |orig-year=1530 |chapter-url=https://books.google.com/books?id=F6tlCB1PdJoC&pg=PA441 |pages=441–442 |quote=cobaltum nostri uocant, Græci cadmiam}}; Cf. index under "{{URL|1=https://books.google.com/books?id=F6tlCB1PdJoC&pg=PT12|2=cobaltum}}".

{{cite book|last=Agricola |first=Georgius |author-link=Georgius Agricola |chapter=Animantium nomina latina, graega, q'ue germanice reddita, quorum author in Libro de subterraneis animantibus meminit |title=Georgii Agricolae Kempnicensis Medici Ac Philosophi Clariss. De Re Metallica Libri XII.: Quibus Officia, Instrumenta, Machinae, Ac Omnia Denique Ad Metallicam Spectantia, Non Modo Luculentissime describuntur; sed & per effigies, suis locis insertas ... ita ob oculos ponuntur, ut clarius tradi non possint |location=Basel |publisher=Sumptibus & Typis Emanuelis König |year=1657 |orig-year=1530 |chapter-url=https://books.google.com/books?id=uCClFLX0CwUC&pg=PA762 |at=p. [762] |quote={{smallcaps|Dæmonum}}: Dæmon subterraneus trunculentus: bergterufel; mitis bergmenlein/kobel/guttel}}

{{cite book|ref={{SfnRef|Agricola|Hoovers trr.|1912}}|last=Agricola |first=Georgius |author-link=Georgius Agricola |others=Translated by Hoover, Herbert Clark and Lou Henry Hoover |title=Georgius Agricola De Re Metallica: Tr. from the 1st Latin Ed. of 1556 (Books I–VIII) |location=London |publisher=The Mining Magazine |year=1912 |url=https://books.google.com/books?id=MfFYAAAAYAAJ&pg=PA112 |at=pp. 112–113}} Describes (and tabulates) German form kobelt; In two volumes: {{URL|1=https://books.google.com/books?id=TvFYAAAAYAAJ |2=Second Part}}, Books IX–XII, contiguous pagination.

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{{Cite journal|last1=Byrne |first1=Erin K. |author1-link= |last2=Theopold |first2=Klaus H. |author2-link= |date=1 February 1987|title=Redox chemistry of tetrakis(1-norbornyl)cobalt. Synthesis and characterization of a cobalt(V) alkyl and self-exchange rate of a Co(III)/Co(IV) couple|journal=Journal of the American Chemical Society|volume=109|issue=4|pages=1282–1283|doi=10.1021/ja00238a066|issn=0002-7863}}

{{cite book |last1=Cracan |first1=Valentin |author1-link=|last2=Banerjee |first2=Ruma |author2-link=Ruma Banerjee |editor1-first=Lucia |editor1-last=Banci |editor1-link=Lucia Banci |series=Metal Ions in Life Sciences |volume=12 |chapter=Chapter 10 Cobalt and Corrinoid Transport and Biochemistry |title=Metallomics and the Cell |date=2013 |pages=333–374 |publisher=Springer |isbn=978-94-007-5560-4 |doi=10.1007/978-94-007-5561-1_10 |pmid=23595677

}} electronic-book {{ISBN |978-94-007-5561-1}} {{issn |1559-0836}} electronic-{{issn |1868-0402}}.

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{{void|Grimms; Hildebrand, Rudolf (1868). Deutsches Wörterbuch, Band 5, s.v. "{{URL|1=https://books.google.com/books?id=ERSZv4n2zpEC&pg=PA1539 |2=Kobel}}"}}

Grimms; Hildebrand, Rudolf (1868). Deutsches Wörterbuch, Band 5, s.v. "{{URL|1=https://books.google.com/books?id=ERSZv4n2zpEC&pg=PA1551 |2=Kobold}}" at "III. 3) nebenformen"

{{cite journal|title=Why we need cobalt |last=Hawkins |first=M. |author-link= |journal=Applied Earth Science|date=2001|volume=110|issue=2|pages =66–71|doi=10.1179/aes.2001.110.2.66|bibcode=2001ApEaS.110...66H|s2cid=137529349}}

{{cite book|title=The Science and Archaeology of Materials: An Investigation of Inorganic Materials |first=Julian |last=Henderson |author-link= |publisher=Routledge|date=2000|isbn=978-0-415-19933-9|url=https://books.google.com/books?id=p9xJ-VpUuNkC|chapter=Glass|page=60}}

{{cite journal|last1=Hebrard |first1=Frédéric |author1-link= |last2=Kalck |first2=Philippe |author2-link= |name-list-style=amp |title=Cobalt-Catalyzed Hydroformylation of Alkenes: Generation and Recycling of the Carbonyl Species, and Catalytic Cycle |journal= Chemical Reviews |date=2009 | volume= 109 |pages= 4272–4282|doi=10.1021/cr8002533|issue=9|pmid=19572688}}

{{cite book|last=House |first=James e. |author-link=James E. House |title=Inorganic chemistry|url=https://books.google.com/books?id=ocKWuxOur-kC&pg=PA767 | access-date=16 May 2011 |date=2008 |publisher=Academic Press |isbn=978-0-12-356786-4 |page=767}}

{{cite journal|last1=Khodakov |first1=Andrei Y. Khodakov |author1-link= |last2=Chu |first2=Wei |author2-link=|last3=Fongarland |first3=Pascal |author3-link= |name-list-style=amp |title=Advances in the Development of Novel Cobalt Fischer-Tropsch Catalysts for Synthesis of Long-Chain Hydrocarbons and Clean Fuels|journal= Chemical Reviews|date= 2007| volume =107|pages=1692–1744|doi=10.1021/cr050972v|issue=5|pmid=17488058}}

{{cite journal|last=Kretschmer |first=Paul |author-link=Paul Kretschmer |title=Weiteres zur Urgeschichte der Inder |journal=Zeitschrift für vergleichende Sprachforschung auf dem Gebiete der indogermanischen Sprachen |volume=55 |date=1928 |url=https://books.google.com/books?id=zYpVkrS47n8C&pg=PA87 |at=p. 89 and p. 87, n2}}

{{OED|cobalt}}; Murray, James A. H. ed. (1908) A New Eng. Dict. II, s.v."[https://books.google.com/books?id=CUPAIeSbvSIC&pg=PA560 cobalt]"

{{cite web|url=http://www.infomine.com/publications/docs/InternationalMining/Chadwick2008t.pdf |title=CAMEC – The Cobalt Champion |publisher=International Mining |date=July 2008

|access-date=18 November 2011}}

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{{cite journal|last=Kerr |first=Paul F. |author-link=Paul F. Kerr |title=Cattierite and Vaesite: New Co-Ni Minerals from the Belgian Kongo |journal =American Mineralogist |volume=30 |date=1945 |pages=83–492 |url=http://www.minsocam.org/ammin/AM30/AM30_483.pdf}}

{{cite dictionary|last=Lecouteux |first=Claude |author-link=Claude Lecouteux |entry=BERGMÄNNCHEN (Bergmännlein, Bergmönch, Knappenmanndl, Kobel, Gütel; gruvrå in Sweden) |title=Encyclopedia of Norse and Germanic Folklore, Mythology, and Magic |publisher=Simon and Schuster |date=2016 |entry-url=https://books.google.com/books?id=vmAoDwAAQBAJ&pg=PT18 |isbn=9781620554814}}, cf. {{in lang|fr}} Lecouteux (2014), "{{URL|1=https://books.google.com/books?id=yZDdDQAAQBAJ&pg=PA1995 |2=BERGMÄNNCHEN}}", Dictionnaire de mythologie germanique, pp. 1995–1996.

{{cite journal |last1=Mandeville |first1=C. |author1-link= |last2=Fulbright |first2=H. |author2-link= |title=The Energies of the γ-Rays from Sb¹²², Cd¹¹⁵, Ir¹⁹², Mn⁵⁴, Zn⁶⁵, and Co⁶⁰ |journal=Physical Review |volume=64 |pages=265–267 |date=1943 |doi=10.1103/PhysRev.64.265 |issue=9–10 |bibcode=1943PhRv...64..265M }}

Mellor, J. W. (1935) {{URL|1=https://books.google.com/books?id=dwdGAQAAMAAJ&q=kowalti |2=Cobalt}} A comprehensive treatise on inorganic and theoretical chemistry vol. XIV, p. 420.

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{{cite book |title=A treatise on metallurgy |first=Frederick |last=Overman |author-link= |publisher=D. Appleton & company |date=1852 |url=https://archive.org/details/atreatiseonmeta01overgoog |pages=[https://archive.org/details/atreatiseonmeta01overgoog/page/n543 631]–637}}

{{cite journal |last=Payne |first =L. R. |author-link=|journal=Occupational Medicine |date=1977 |volume=27 |pages=20–25 |title=The Hazards of Cobalt|doi=10.1093/occmed/27.1.20 |pmid=834025 |issue=1}}

{{cite journal|pmc=3586865|year=2012|last1=Pourkhabbaz |first1=A |author-link= |title=Investigation of Toxic Metals in the Tobacco of Different Iranian Cigarette Brands and Related Health Issues|journal=Iranian Journal of Basic Medical Sciences|volume=15|issue=1|pages=636–644|last2=Pourkhabbaz|first2=H|pmid=23493960}}

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{{cite journal |journal=Statistica |date=2020 |title=Morocco Cobalt Production |first=Amna |last=Puri-Mirza |author-link= |url=https://www.statista.com/statistics/793590/morocco-cobalt-production/}}

{{cite journal|journal=Archaeometry|volume=43|issue=4|date=2003|title=Aspects of the Production of Cobalt-blue Glass in Egypt |first=Thilo |last=Rehren |author-link= |doi=10.1111/1475-4754.00031|pages=483–489}}

{{cite book|title=Organometallics in Environment and Toxicology (Metal Ions in Life Sciences)|date=2010|publisher=Royal Society of Chemistry Publishing|location=Cambridge, UK |isbn=978-1-84755-177-1 |page=75 |editor1-first=Astrid |editor1-last=Sigel |editor1-link= |editor2-first=Helmut |editor2-last=Sigel |editor2-link=|editor3-first=Roland |editor3-last=Sigel |editor3-link=}}

{{cite book|last1=Starks |first1=Charles M. |author1-link= |last2=Liotta |first2=Charles Leonard |author2= |last3=Halpern |first3=Marc |author3= |title=Phase-transfer catalysis: fundamentals, applications, and industrial perspectives|url=https://books.google.com/books?id=-QCGckdeKAkC&pg=PA600 |access-date=16 May 2011 |date=1994 |publisher=Springer |isbn=978-0-412-04071-9 |page=600}}

{{cite journal|last1=Talhout |first1=Reinskje |author1-link= |last2=Schulz |first2=Thomas |author2-link= |last3=Florek |first3=Ewa |author3-link=|last4=Van Benthem|first4=Jan |author4-link=|last5=Wester |first5=Piet |author5-link=|last6=Opperhuizen |first6=Antoon |author6-link=|title=Hazardous Compounds in Tobacco Smoke |journal=International Journal of Environmental Research and Public Health|volume=8|issue=12|year=2011|pages=613–628|issn=1660-4601|doi=10.3390/ijerph8020613|pmid=21556207|pmc=3084482|doi-access=free}}

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{{cite journal |title=Ueber die Bereitung einer blauen Farbe aus Kobalt, die eben so schön ist wie Ultramarin. Vom Bürger Thenard |first=A. F. |last=Gehlen |author-link=Adolph Ferdinand Gehlen |url=https://books.google.com/books?id=UGsMAQAAIAAJ&pg=RA1-PA506 |journal=Neues Allgemeines Journal der Chemie, Band 2 |publisher=H. Frölich |date=1803}} (German translation from L. J. Thénard; Journal des Mines; Brumaire 12 1802; p 128–136)

{{cite journal |title=The charge of the guns of peace |journal=Metallurgist |volume=14 |issue=5 |date=1970 |doi=10.1007/BF00739447 |pages=334–336 |first =S. |last=Venetskii |author1-link= |s2cid=137225608}}

{{cite book|last=Verardi |first=Donato |author-link= |title=Aristotelianism and Magic in Early Modern Europe: Philosophers, Experimenters and Wonderworkers |publisher=Bloomsbury Publishing |year=2023 |url=https://books.google.com/books?id=7XS5EAAAQBAJ&pg=PA85 |page=85 |isbn=9781350357174}}

{{cite journal|journal =Journal of the Minerals, Metals and Materials Society|volume=58|issue=10|date=2006|doi=10.1007/s11837-006-0201-y|pages=47–50|title=Cobalt—Its recovery, recycling, and application|first=Shijie|last=Wang |author-link= |bibcode=2006JOM....58j..47W|s2cid=137613322}}

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{{cite journal |doi =10.1021/ie50143a048 |title =Colors Developed by Cobalt Oxides |date =1921 |last1=Witteveen |first1=H. J. |author1-link= |last2 =Farnau |first2 =E. F. |author2-link=|journal =Industrial & Engineering Chemistry |volume =13 |pages =1061–1066 |issue =11 |url =https://zenodo.org/record/1428758}}

{{cite book|last=Wothers |first=Peter |author-link=Peter Wothers |title=Antimony, Gold, and Jupiter's Wolf: How the elements were named|publisher=Oxford University Press |year=2019 |url=https://books.google.com/books?id=PFS_DwAAQBAJ&pg=PA49 |pages=47–49 |isbn=9780192569905}}

{{cite book|last=Yamada |first=Kazuhiro |author-link= |editor1-last=Sigel |editor1-first=Astrid |editor1-link= |editor2-last=Sigel |editor2-first=Helmut |editor2-link= |editor3-last=Sigel |editor3-first=Roland K. O. |editor3-link= |title=Interrelations between Essential Metal Ions and Human Diseases |series=Metal Ions in Life Sciences |volume=13 |date=2013 |publisher=Springer |pages=295–320 |chapter=Chapter 9. Cobalt: Its Role in Health and Disease |doi=10.1007/978-94-007-7500-8_9 |pmid=24470095 |isbn=978-94-007-7499-5

}}

{{cite journal|last1=Zhang |first1=P. |author1-link= |title=Recovery of metal values from spent nickel–metal hydride rechargeable batteries|journal=Journal of Power Sources|volume=77|pages=116–122|date=1999|doi=10.1016/S0378-7753(98)00182-7|issue=2 |last2=Yokoyama |first2=Toshiro |author2-link= |last3=Itabashi |first3=Osamu |author3-link= |last4=Wakui |first4=Yoshito |author4-link= |last5=Suzuki |first5=Toshishige M. |author5-link= |last6=Inoue |first6=Katsutoshi |author6-link= |bibcode=1999JPS....77..116Z }}

}}

{{Anchor|External links to peer-reviewed journals}}

{{Refbegin}}

• {{cite journal |pmid=22142288 |year=2012 |last1=Harper |first1=E. M. |title=Tracking the metal of the goblins: Cobalt's cycle of use |journal=Environmental Science & Technology |volume=46 |issue=2 |pages=1079–86 |last2=Kavlak |first2=G. |last3=Graedel |first3=T. E. |doi=10.1021/es201874e |bibcode=2012EnST...46.1079H|s2cid=206948482 }}
• {{cite journal |pmid=22139330 |year=2012 |last1=Narendrula |first1=R. |title=Comparative soil metal analyses in Sudbury (Ontario, Canada) and Lubumbashi (Katanga, DR-Congo) |journal=Bulletin of Environmental Contamination and Toxicology |volume=88 |issue=2 |pages=187–92 |last2=Nkongolo |first2=K. K. |last3=Beckett |first3=P. |doi=10.1007/s00128-011-0485-7 |bibcode=2012BuECT..88..187N |s2cid=34070357}}
• {{cite journal |pmid=20466452 |year=2010 |last1=Pauwels |first1=H. |title=The combined effect of abandoned mines and agriculture on groundwater chemistry |journal=Journal of Contaminant Hydrology |volume=115 |issue=1–4 |pages=64–78 |last2=Pettenati |first2=M. |last3=Greffié |first3=C. |doi=10.1016/j.jconhyd.2010.04.003 |bibcode=2010JCHyd.115...64P}}
• {{cite journal |pmid=16634226 |year=2006 |last1=Bulut |first1=G. |title=Recovery of copper and cobalt from ancient slag |journal=Waste Management & Research |volume=24 |issue=2 |pages=118–24 |doi=10.1177/0734242X06063350 |bibcode=2006WMR....24..118B |s2cid=24931095}}
• {{cite journal |pmid=11844517 |year=2002 |last1=Jefferson |first1=J. A. |title=Excessive erythrocytosis, chronic mountain sickness, and serum cobalt levels |journal=Lancet |volume=359 |issue=9304 |pages=407–8 |last2=Escudero |first2=E. |last3=Hurtado |first3=M. E. |last4=Pando |first4=J. |last5=Tapia |first5=R. |last6=Swenson |first6=E. R. |last7=Prchal |first7=J. |last8=Schreiner |first8=G. F. |last9=Schoene |first9=R. B. |last10=Hurtado |first10=A. |last11=Johnson |first11=R. J. |doi=10.1016/s0140-6736(02)07594-3 |s2cid=12319751}}
• {{cite journal |pmid=10827501 |year=1999 |last1=Løvold |first1=T. V. |title=Cobalt mining factory--diagnoses 1822-32 |journal=Tidsskrift for den Norske Laegeforening |volume=119 |issue=30 |pages=4544–6 |last2=Haugsbø |first2=L.}}
• {{cite journal |pmid=9718743 |year=1998 |last1=Bird |first1=G. A. |title=Bioaccumulation of radionuclides in fertilized Canadian Shield lake basins |journal=The Science of the Total Environment |volume=218 |issue=1 |pages=67–83 |last2=Hesslein |first2=R. H. |last3=Mills |first3=K. H. |last4=Schwartz |first4=W. J. |last5=Turner |first5=M. A. |doi=10.1016/s0048-9697(98)00179-x |bibcode=1998ScTEn.218...67B}}
• {{cite journal |pmid=2178966 |year=1990 |last1=Nemery |first1=B. |title=Metal toxicity and the respiratory tract |journal=The European Respiratory Journal |volume=3 |issue=2 |pages=202–19|doi=10.1183/09031936.93.03020202 |doi-access=free }}
• {{cite journal |pmid=7023929 |pmc=1568837 |year=1981 |last1=Kazantzis |first1=G. |title=Role of cobalt, iron, lead, manganese, mercury, platinum, selenium, and titanium in carcinogenesis |journal=Environmental Health Perspectives |volume=40 |pages=143–61 |doi=10.1289/ehp.8140143|bibcode=1981EnvHP..40..143K }}
• {{cite journal |pmid=1111264 |year=1975 |last1=Kerfoot |first1=E. J. |title=Cobalt metal inhalation studies on miniature swine |journal=American Industrial Hygiene Association Journal |volume=36 |issue=1 |pages=17–25 |last2=Fredrick |first2=W. G. |last3=Domeier |first3=E. |doi=10.1080/0002889758507202}}

{{Refend}}

{{Commons}}

{{Wiktionary|cobalt}}

• {{cite EB9 |wstitle = Cobalt |volume= VI | pages=81-83 |short=1}}
• [http://www.periodicvideos.com/videos/027.htm Cobalt] at The Periodic Table of Videos (University of Nottingham)
• [https://www.cdc.gov/niosh/topics/cobalt/ Centers for Disease and Prevention – Cobalt]

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