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About Cobalt

Cobalt Bohr

Much like the “kupfernickel”--devil’s copper--ores that had been so named for failing to produce the copper they were thought to contain, cobalt’s ores were frustrating to miners. Not only did they fail to yield useful metals, these ores additionally produced toxic arsenic oxide when smelted. The ores were therefore named after kobolds--goblins that German miners frequently blamed for mining mishaps. When, around 1935, the Swedish chemist Georg Brandt succeeded in isolating cobalt metal, he named his newly discovered element for its ore.

In addition to discovering cobalt, Brandt demonstrated that cobalt compounds had been unknowingly used to provide coloring in smalt, a blue glass, since the middle ages. In the late eighteenth and early nineteenth century, green and blue pigments based on cobalt were developed and came into widespread use for coloring ceramics, jewelry, and paint. These applications for cobalt remain relevant in modern times, but today cobalt is used most often in metallic form.

The majority of cobalt consumed in the United States is used in the production of superalloys, metal formulations which most often find use in arenas where resistance to extreme conditions are required, such as in the components of jet engines or high-speed drill bits. Superalloys are also sometimes used in medical implants such as hip replacement, though these implants must be monitored for damage, as metal nanoparticles produced by wear are easily absorbed by and distributed through the body. Cobalt found in cobalamin, also known as vitamin B12, is an essential nutrient, but excess free cobalt ions in the body have toxic effects.

Cobalt is also used in other alloy applications. It is found in both Alnico and samarium-cobalt magnets, both of which are used widely in industry. Cobalt is also found in combination with primary electrode metals in lithium ion, nickel-cadmium, and nickel metal hydride batteries. Cobalt’s attractive appearance, extreme hardness, and resistance to oxidation lend it to use as a metal for plating of other materials, either alone or as the base for further coatings such as porcelain enamels. Platinum used in jewelry making contains five percent cobalt, as this produces an alloy that is suitable for highly detailed casting.

There are two other major uses for cobalt in industry. The first is as a catalyst: cobalt compounds are used industrially to produce polymer precursors, remove sulfurous impurities from petroleum, and improve adhesion of steel to rubber for the production of steel-belted tires. Additionally, cobalt catalysts are added as drying agents to paints and varnishes, and used in a variety of other chemical processes, on both industrial and lab-scales.The second other major use is as a binder in cemented carbides, extremely hard materials used in machining metals such as steel.

Finally, cobalt radioisotopes serve a few notable functions. Cobalt-60 is a radioactive isotope used to produce gamma rays for sterilizing food and medical supplies and for use in both medical radiotherapy and the in the production of industrial radiographs. Cobalt-57 is used as a tracer in medical imaging, primarily for observing vitamin B12 uptake.

The main cobalt ores are cobaltite, erythrite, glaucodot, and skutterudite, all of which are exploited commercially, but a substantial amount of the metal is also obtained from processing byproducts of copper and nickel mining. Cobalt catalysts and cobalt-alloy scrap may also be recycled to recover high purity cobalt.

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Summary. Cobalt is often alloyed with iron, nickel and other metals to make Alnico, an alloy of unusual magnetic strength with many important uses. Samarium-cobalt, for instance, is one of the highest strength magnet alloys known. Cobalt compounds are used to produce a brilliant and permanent blue color in ceramic glazes, glass, High Purity (99.999%) Cobalt Oxide (Co3O4) Powderpottery, tiles, and enamels. Co-60, a commercially important radioisotope, is useful as a radioactive tracer and gamma ray source. High Purity (99.999%) Cobalt (Co) Sputtering TargetCobalt is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Cobalt nanoparticles and nanopowders are also available. Cobalt oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Cobalt fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Cobalt is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Cobalt Properties

Cobalt(Co) atomic and molecular weight, atomic number and elemental symbolCobalt is a Block D, Group 9, Period 4 element. The number of electrons in each of cobalt's shells is 2, 8, 15, 2 and its electron configuration is [Ar] 3d7 4s2. Cobalt Bohr ModelThe cobalt atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-48-4, cobalt has a Elemental Cobaltlustrous gray appearance. Cobalt is found in cobaltite, erythrite, glaucodot and skutterudite ores, but is not found free in nature. Cobalt was first discovered by George Brandt in 1732. The origin of the word Cobalt comes from the German word 'Kobalt or Kobold' which translates as "goblin", "elf" or "evil spirit".

Symbol: Co
Atomic Number: 27
Atomic Weight: 58.9332
Element Category: transition metal
Group, Period, Block: 9, 4, d
Color: lustrous, metallic, grayish tinge /bluish-white
Other Names: Cobaltum, Cobalto, Kobalt, Kobolt
Melting Point: 1495.0 °C, 2723.0 °F, 1768.15 K
Boiling Point: 2870.0 °C, 5198.0 °F, 3143.15 K
Density: 8.9 gm/cm3
Liquid Density @ Melting Point: 7.75 g·cm3
Density @ 20°C: 8.90 g/cm3
Density of Solid: 8900 kg·m3
Specific Heat: 0.109 Cal/g/K @ 25°C
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 15.2
Heat of Vaporization (kJ·mol-1): 382.4
Heat of Atomization (kJ·mol-1): 423.082
Thermal Conductivity: 1.0 W/cm/K @ 298.2 K
Thermal Expansion: (25 °C) 13.0 µm·m-1·K-1
Electrical Resistivity: 6.24 µΩ·m @ 20°C
Tensile Strength: N/A
Molar Heat Capacity: 24.81 J·mol-1·K-1
Young's Modulus: 209 GPa
Shear Modulus: 75 GPa
Bulk Modulus: 180 GPa
Poisson Ratio: 0.31
Mohs Hardness: 5
Vickers Hardness: 1043 MPa
Brinell Hardness: 700 MPa
Speed of Sound: (20 °C) 4720 m·s-1
Pauling Electronegativity: 1.88
Sanderson Electronegativity: 2.56
Allred Rochow Electronegativity: 1.7
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.12
Reflectivity (%): 67
Refractive Index: N/A
Electrons: 27
Protons: 27
Neutrons: 32
Electron Configuration: [Ar] 3d7 4s2
Atomic Radius: 125 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 126±3 (low spin), 150±7 (high spin) pm
Covalent Radius (Å): 1.18
Van der Waals Radius: 200 pm
Oxidation States: 5, 4, 3, 2, 1, -1 (amphoteric oxide)
Phase: Solid
Crystal Structure: Hexagonal
Magnetic Ordering: ferromagnetic
Electron Affinity (kJ·mol-1) 63.851
1st Ionization Energy: 760.41 kJ·mol-1
2nd Ionization Energy: 1648.27 kJ·mol-1
3rd Ionization Energy: 3232.28 kJ·mol-1
CAS Number: 7440-48-4
EC Number: 231-158-0
MDL Number: MFCD00010935
Beilstein Number: N/A
SMILES Identifier: [Co]
InChI Identifier: InChI=1S/Co
PubChem CID: 104730
ChemSpider ID: 94547
Earth - Total: 840 ppm
Mercury - Total: 1690 ppm
Venus - Total: 820 ppm
Earth - Seawater (Oceans), ppb by weight: 0.08
Earth - Seawater (Oceans), ppb by atoms: 0.008
Earth -  Crust (Crustal Rocks), ppb by weight: 30000
Earth -  Crust (Crustal Rocks), ppb by atoms: 10000
Sun - Total, ppb by weight: 4000
Sun - Total, ppb by atoms: 70
Stream, ppb by weight: 0.2
Stream, ppb by atoms: 0.003
Meterorite (Carbonaceous), ppb by weight: 600000
Meterorite (Carbonaceous), ppb by atoms: 200000
Typical Human Body, ppb by weight: 20
Typical Human Body, ppb by atom: 2
Universe, ppb by weight: 3000
Universe, ppb by atom: 60
Discovered By: Georg Brandt
Discovery Date: 1732
First Isolation: N/A

Health, Safety & Transportation Information for Cobalt

Toxicity of cobalt and its compounds are mild by skin contact and moderate by ingestion. Safety data for Cobalt and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Cobalt.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Danger
Hazard Statements H317-H334-H413
Hazard Codes Xn
Risk Codes 42/43-53
Safety Precautions 22-24-37-61
RTECS Number GF8750000
Transport Information UN 3089 4.1/PG 2
WGK Germany nwg
Globally Harmonized System of
Classification and Labelling (GHS)
Health Hazard

Cobalt Isotopes

Naturally occurring cobalt has 1 stable isotope: 59Co.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
47Co 47.01149(54)# N/A Unknown 7/2-# N/A 339.16 -
48Co 48.00176(43)# N/A p to 47Fe (6+) N/A 356.55 -
49Co 48.98972(28)# <35 ns p to 48Fe 7/2-# N/A 375.81 -
50Co 49.98154(18)# 44(4) ms β+ + p to 49Mn; β+ to 50Fe (6+) N/A 391.34 -
51Co 50.97072(16)# 60# ms [>200 ns] p to 51Fe 7/2-# N/A 409.67 -
52Co 51.96359(7)# 115(23) ms p to 52Fe 0+ N/A 424.27 -
53Co 52.954219(19) 242(8) ms p to 53Fe 7/2- N/A 440.73 -
54Co 53.9484596(8) 193.28(7) ms p to 54Fe 4+ N/A 454.4 -
55Co 54.9419990(8) 17.53(3) h EC to 55Fe 7/2- 4.822 469 -
56Co 55.9398393(23) 77.233(27) d EC to 56Fe 2+ 3.85 478.94 -
57Co 56.9362914(8) 271.74(6) d EC to 57Fe 7/2- 4.72 489.82 -
58Co 57.9357528(13) 70.86(6) d EC to 58Fe 5+ 4.04 498.83 -
59Co 58.9331950(7) STABLE - 7/2- 4.627 508.77 100
60Co 59.9338171(7) 5.2713(8) y β- to 60Ni 2+ 3.799 516.85 -
61Co 60.9324758(10) 1.650(5) h β- to 61Ni 7/2- N/A 525.86 -
62Co 61.934051(21) 1.50(4) min β- to 62Ni 1+ N/A 532.07 -
63Co 62.933612(21) 26.9(4) s β- to 63Ni (7/2)- N/A 541.08 -
64Co 63.935810(21) 0.30(3) s β- to 64Ni (3+) N/A 547.3 -
65Co 64.936478(14) 1.20(6) s β- to 65Ni (7/2-)# N/A 554.44 -
66Co 65.93976(27) 0.18(1) s β- to 66Ni (7-) N/A 559.73 -
67Co 66.94089(34) 0.425(20) s β- to 67Ni 7/2-# N/A 566.88 -
68Co 67.94487(34) 0.199(21) s β- to 68Ni (6-) N/A 571.23 -
69Co 68.94632(36) 227(13) ms β- to 69Ni; β- + n to 68Ni 7/2-# N/A 577.44 -
70Co 69.9510(9) 119(6) ms β- to 70Ni; β- + n to 69Ni (6-,7-) N/A 580.86 -
71Co 70.9529(9) 97(2) ms β- to 71Ni; β- + n to 70Ni 7/2-# N/A 588.01 -
72Co 71.95781(64)# 62(3) ms β- to 72Ni; β- + n to 71Ni 0+ N/A 591.43 -
73Co 72.96024(75)# 41(4) ms Unknown 7/2-# N/A 596.72 -
74Co 73.96538(86)# 50# ms [>300 ns] Unknown 0 N/A 600.14 -
75Co 74.96833(86)# 40# ms [>300 ns] Unknown 7/2 N/A 605.42 -
Cobalt Elemental Symbol

Recent Research & Development for Cobalt

  • J.M. Xu, J. Zhang, B.B. Wang, F. Liu, Shape-regulated synthesis of cobalt oxide and its gas-sensing property, Journal of Alloys and Compounds, Volume 619, 15 January 2015
  • Zhuang-hao Zheng, Ping Fan, Guang-xing Liang, Dong-ping Zhang, Influence of deposition temperature on the microstructure and thermoelectric properties of antimonide cobalt thin films prepared by ion beam sputtering deposition, Journal of Alloys and Compounds, Volume 619, 15 January 2015
  • Dragoslav Ilić, Verica V. Jevtić, Miorad M. Vasojević, Miodrag Ž. Jelić, Ivana D. Radojević, Ljiljana R. Čomić, Slađana B. Novaković, Goran A. Bogdanović, Ivan Potočňák, Srećko R. Trifunović, Stereospecific ligands and their complexes. Part XXI. Synthesis, characterization, circular dichroism and antimicrobial activity of cobalt(III) complexes with some edda-type of ligands. Crystal structure of potassium-Δ-(−)589-s-cis-oxalato-(S,S)-ethylenediamine-N,N′-di-(2-propanoato)-cobaltate(III)-semihydrate, K-Δ-(−)589-s-cis-[Co(S,S-eddp)(ox)]·0.5H2O, Polyhedron, Volume 85, 8 January 2015
  • Carmen Cretu, Ramona Tudose, Liliana Cseh, Wolfgang Linert, Eleftherios Halevas, Antonios Hatzidimitriou, Otilia Costisor, Athanasios Salifoglou, Schiff base coordination flexibility toward binary cobalt and ternary zinc complex assemblies. The case of the hexadentate ligand N,N′-bis[(2-hydroxybenzilideneamino)-propyl]-piperazine, Polyhedron, Volume 85, 8 January 2015
  • Michael Bubnov, Nina Skorodumova, Alla Arapova, Natalya Smirnova, Artem Bogomyakov, Maxim Samsonov, Vladimir Cherkasov, Gleb Abakumov, New bis-o-semiquinonato cobalt complexes with 1,10-phenanthroline ligands, Polyhedron, Volume 85, 8 January 2015
  • Mahendra Ghosh, Manas Layek, Michel Fleck, Rajat Saha, Debasis Bandyopadhyay, Synthesis, crystal structure and antibacterial activities of mixed ligand copper(II) and cobalt(II) complexes of a NNS Schiff base, Polyhedron, Volume 85, 8 January 2015
  • Kihun Jang, Seongil Yu, Sung-Hyeon Park, Hak-Sung Kim, Heejoon Ahn, Intense pulsed light-assisted facile and agile fabrication of cobalt oxide/nickel cobaltite nanoflakes on nickel-foam for high performance supercapacitor applications, Journal of Alloys and Compounds, Volume 618, 5 January 2015
  • Ying Deng, Xiang Xiong, J.P. Zou, Ling Deng, M.J. Tu, Control of morphology and structure for β-Co nanoparticles from cobalt oxalate and research on its phase-change mechanism, Journal of Alloys and Compounds, Volume 618, 5 January 2015
  • G. Vignesh, Y. Manojkumar, K. Sugumar, S. Arunachalam, Spectroscopic investigation on the interaction of some polymer–cobalt(III) complexes with serum albumins, Journal of Luminescence, Volume 157, January 2015
  • Poonam Pahuja, R.K. Kotnala, R.P. Tandon, Effect of rare earth substitution on properties of barium strontium titanate ceramic and its multiferroic composite with nickel cobalt ferrite, Journal of Alloys and Compounds, Volume 617, 25 December 2014