Cobalt

Characteristics and Compounds of Cobalt
– Cobalt is a ferromagnetic metal with a specific gravity of 8.9.
– It has a Curie temperature of 1,115°C (2,039°F) and a magnetic moment of 1.6-1.7 Bohr magnetons per atom.
– Cobalt has two crystallographic structures: hcp and fcc.
– It is a weakly reducing metal protected from oxidation by a passivating oxide film.
– Common oxidation states of cobalt include +2 and +3.
– Cobalt compounds include the pink-colored metal aquo complex [Co(H2O)6]2+, the intensely blue [CoCl4]2-, and various cobalt oxides such as CoO, Co3O4, and Co2O3.
– Cobalt oxides are antiferromagnetic at low temperatures.
– Cobalt halides include CoF2 (pink), CoCl2 (blue), CoBr2 (green), and CoI2 (blue-black).
– Cobalt forms coordination complexes with ligands, such as hexaaquocobalt(II) [Co(H2O)6]2+ and triscarbonatocobaltate(III) [Co(CO3)3]2-.
– Cobaltocene, a structural analog to ferrocene, is a coordination compound that is sensitive to oxidation.

Isotopes and History of Cobalt
– The only stable cobalt isotope on Earth is Co.
– There are 22 characterized radioisotopes of cobalt, with the most stable one being Co with a half-life of 5.2714 years.
– Cobalt compounds have been used for centuries to color glass, glazes, and ceramics.
– Cobalt has been detected in ancient artifacts from Egypt, Persia, and China.
– The word “cobalt” is derived from the German term “kobalt” meaning goblin.
– Cobalt was discovered by Swedish chemist Georg Brandt in 1735.
– Cobalt mining operations shifted from Europe to New Caledonia and the Congo in the 19th century.

Occurrence of Cobalt
– Cobalt is produced in supernovae through the r-process.
– It comprises 0.0029% of the Earth’s crust and is frequently associated with nickel.
– Free cobalt is not found on Earth’s surface due to its reactivity with oxygen.
– Cobalt compounds can be found in rocks, soils, plants, and animals.
– In the ocean, cobalt is a trace metal involved in photosynthesis and nitrogen fixation.

Uses, Demand, and Extraction of Cobalt
– Cobalt is used in rechargeable batteries, superalloys, and catalysts.
– It is a key component in materials used for renewable energy.
– Cobalt demand has accelerated in the 21st century.
– The Democratic Republic of the Congo (DRC) currently produces 63% of the world’s cobalt.
– Cobalt is primarily obtained as a by-product of nickel and copper mining and smelting.
– Froth flotation is used to separate cobalt from copper and nickel ores.
– Cobalt can also be obtained through aluminothermic reaction, reduction with carbon, or leaching from copper smelting slag.

Environmental and Social Concerns, and Supply Chain Initiatives
– Cobalt is considered toxic for marine environments at high concentrations.
– Cobalt mining pollutes the vicinity and exposes wildlife and communities to toxic metals.
– Child labor is used in cobalt mining in African artisanal mines.
– There is a global push for sustainable and responsible sourcing of cobalt, with initiatives by the EU and major car manufacturers.
– Major car manufacturers and mining companies are participating in initiatives for responsible cobalt production.
– Traceability of the cobalt supply chain is a focus for sustainable sourcing. Source:  https://en.wikipedia.org/wiki/Cobalt

Cobalt (Wikipedia)

For the gas with chemical formula CO, see carbon monoxide.

This article is about the chemical element. For other uses, see Cobalt (disambiguation).

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, somewhat brittle, gray metal.

Cobalt, ₂₇Co

Cobalt
Pronunciation	/ˈkoʊbɒlt/ ⓘ
Appearance	Hard lustrous bluish gray metal
Standard atomic weightAr°(Co)
	58.933194±0.000003 58.933±0.001 (abridged)
Cobalt in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson – ↑ Co ↓ Rh iron ← cobalt → nickel
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
Phaseat 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
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 P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1790 1960 2165 2423 2755 3198
Atomic properties
Oxidation states	common: +2, +3 −3, −1, 0, +1, +4, +5
Electronegativity	Pauling scale: 1.88
Ionization energies	1st: 760.4 kJ/mol 2nd: 1648 kJ/mol 3rd: 3232 kJ/mol (more)
Atomic radius	empirical: 125 pm
Covalent radius	Low spin: 126±3 pm High spin: 150±7 pm
Spectral lines of cobalt
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal close-packed (hcp) (hP2)
Lattice constants	a = 250.71 pm c = 407.00 pm (at 20 °C)
Thermal expansion	12.9×10−6/K (at 20 °C)
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 v e
Main isotopes Decay abun­dance half-life(t1/2) mode pro­duct 56Co synth 77.236 d β+ 56Fe 57Co synth 271.811 d ε 57Fe 58Co synth 70.844 d β+ 58Fe 59Co 100% stable 60Co trace 5.2714 y β−100% 60Ni
Category: Cobalt view talk edit | references

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. 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%.

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.

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.

The name cobalt derives from a type of ore considered a nuisance by 16th century German silver miners, which in turn may have been named from a spirit or goblin held superstitiously responsible for it; this spirit is considered equitable to the kobold (a household spirit) by some, or, categorized as a gnome (mine spirit) by others.