Global InformationCobalt information
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| Cobalt | ||||||||||||||||||||||||||||||||||||
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| Pronunciation | /ˈkoʊbɒlt/ ⓘ[1] | |||||||||||||||||||||||||||||||||||
| Appearance | hard lustrous bluish gray metal | |||||||||||||||||||||||||||||||||||
| Standard atomic weight Ar°(Co) | ||||||||||||||||||||||||||||||||||||
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| Cobalt in the periodic table | ||||||||||||||||||||||||||||||||||||
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| Atomic number (Z) | 27 | |||||||||||||||||||||||||||||||||||
| Group | group 9 | |||||||||||||||||||||||||||||||||||
| Period | period 4 | |||||||||||||||||||||||||||||||||||
| Block | d-block | |||||||||||||||||||||||||||||||||||
| Electron configuration | [Ar] 3d7 4s2 | |||||||||||||||||||||||||||||||||||
| Electrons per shell | 2, 8, 15, 2 | |||||||||||||||||||||||||||||||||||
| Physical properties | ||||||||||||||||||||||||||||||||||||
| Phase at STP | solid | |||||||||||||||||||||||||||||||||||
| Melting point | 1768 K (1495 °C, 2723 °F) | |||||||||||||||||||||||||||||||||||
| Boiling point | 3200 K (2927 °C, 5301 °F) | |||||||||||||||||||||||||||||||||||
| Density (at 20° C) | 8.834 g/cm3 [4] | |||||||||||||||||||||||||||||||||||
| when liquid (at m.p.) | 7.75 g/cm3 | |||||||||||||||||||||||||||||||||||
| Heat of fusion | 16.06 kJ/mol | |||||||||||||||||||||||||||||||||||
| Heat of vaporization | 377 kJ/mol | |||||||||||||||||||||||||||||||||||
| Molar heat capacity | 24.81 J/(mol·K) | |||||||||||||||||||||||||||||||||||
Vapor pressure
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| Atomic properties | ||||||||||||||||||||||||||||||||||||
| Oxidation states | −3, −1, 0, +1, +2, +3, +4, +5[5] (an amphoteric oxide) | |||||||||||||||||||||||||||||||||||
| Electronegativity | Pauling scale: 1.88 | |||||||||||||||||||||||||||||||||||
| Ionization energies |
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| Atomic radius | empirical: 125 pm | |||||||||||||||||||||||||||||||||||
| Covalent radius | Low spin: 126±3 pm High spin: 150±7 pm | |||||||||||||||||||||||||||||||||||
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| Other properties | ||||||||||||||||||||||||||||||||||||
| Natural occurrence | primordial | |||||||||||||||||||||||||||||||||||
| Crystal structure | hexagonal close-packed (hcp) (hP2) | |||||||||||||||||||||||||||||||||||
| Lattice constants |  c = 407.00 pm (at 20 °C)[4] | |||||||||||||||||||||||||||||||||||
| Thermal expansion | 12.9×10−6/K (at 20 °C)[a] | |||||||||||||||||||||||||||||||||||
| Thermal conductivity | 100 W/(m⋅K) | |||||||||||||||||||||||||||||||||||
| Electrical resistivity | 62.4 nΩ⋅m (at 20 °C) | |||||||||||||||||||||||||||||||||||
| Magnetic ordering | ferromagnetic | |||||||||||||||||||||||||||||||||||
| Young's modulus | 209 GPa | |||||||||||||||||||||||||||||||||||
| Shear modulus | 75 GPa | |||||||||||||||||||||||||||||||||||
| Bulk modulus | 180 GPa | |||||||||||||||||||||||||||||||||||
| Speed of sound thin rod | 4720 m/s (at 20 °C) | |||||||||||||||||||||||||||||||||||
| Poisson ratio | 0.31 | |||||||||||||||||||||||||||||||||||
| Mohs hardness | 5.0 | |||||||||||||||||||||||||||||||||||
| Vickers hardness | 1043 MPa | |||||||||||||||||||||||||||||||||||
| Brinell hardness | 470–3000 MPa | |||||||||||||||||||||||||||||||||||
| CAS Number | 7440-48-4 | |||||||||||||||||||||||||||||||||||
| History | ||||||||||||||||||||||||||||||||||||
| Discovery and first isolation | Georg Brandt (1735) | |||||||||||||||||||||||||||||||||||
| Isotopes of cobalt | ||||||||||||||||||||||||||||||||||||
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Cobalt is a chemical element; it has symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silvery metal.
Cobalt-based blue pigments (cobalt blue) have been used since antiquity for jewelry and paints, and to impart a distinctive blue tint to glass. The color was long thought to be due to the metal bismuth. Miners had long used the name kobold ore (German for goblin ore) for some of the blue pigment-producing minerals. They were so named because they were poor in known metals and gave off poisonous arsenic-containing fumes when smelted.[7] In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), which was ultimately named for the kobold.
Today, some cobalt is produced specifically from one of a number of metallic-lustered ores, such as cobaltite (CoAsS). The element is more usually produced as a by-product of copper and nickel mining. The Copperbelt in the Democratic Republic of the Congo (DRC) and Zambia yields most of the global cobalt production. World production in 2016 was 116,000 tonnes (114,000 long tons; 128,000 short tons) (according to Natural Resources Canada), and the DRC alone accounted for more than 50%.[8]
Cobalt is primarily used in lithium-ion batteries, and in the manufacture of magnetic, wear-resistant and high-strength alloys. The compounds cobalt silicate and cobalt(II) aluminate (CoAl2O4, cobalt blue) give a distinctive deep blue color to glass, ceramics, inks, paints and varnishes. Cobalt occurs naturally as only one stable isotope, cobalt-59. Cobalt-60 is a commercially important radioisotope, used as a radioactive tracer and for the production of high-energy gamma rays. Cobalt is also used in the petroleum industry as a catalyst when refining crude oil. This is to purge it of sulfur, which is very polluting when burned and causes acid rain.[9]
Cobalt is the active center of a group of coenzymes called cobalamins. Vitamin B12, the best-known example of the type, is an essential vitamin for all animals. Cobalt in inorganic form is also a micronutrient for bacteria, algae, and fungi.
- ^ "cobalt". Oxford English Dictionary (2nd ed.). Oxford University Press. 1989.
- ^ "Standard Atomic Weights: Cobalt". CIAAW. 2017.
- ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (May 4, 2022). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
- ^ a b Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 1117–1119. ISBN 978-0-08-037941-8.
- ^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
- ^ "cobalt". Oxford English Dictionary (2nd ed.). Oxford University Press. 1989.
- ^ Danielle Bochove (November 1, 2017). "Electric car future spurs Cobalt rush: Swelling demand for product breathes new life into small Ontario town". Vancouver Sun. Bloomberg. Archived from the original on July 28, 2019.
- ^ "Catalysts". Cobalt Institute. Archived from the original on August 16, 2023. Retrieved August 15, 2023.
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