Cobalt

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Attribution: Alchemist-hp

Animated Cobalt

History

From the German word Kobald, goblin or evil spirit; also from the Greek cobalos, mine. George Brandt discovered cobalt in 1735.

Sources

Cobalt occurs in the minerals cobaltite, smaltite, and erythrite, and is often associated with nickel, silver, lead, copper, and iron ores, from which it is most frequently obtained as a by-product. It is also present in meteorites.

Important ore deposits are found in Zaire, Morocco, and Canada. The U.S. Geological Survey has announced that the bottom of the north central Pacific Ocean may have cobalt-rich deposits at relatively shallow depths in water close to the the Hawaiian Islands and other U.S. Pacific territories.

Uses

It is alloyed with iron, nickel and other metals to make Alnico, an alloy of unusual magnetic strength with many important uses. Stellite alloys, containing cobalt, chromium, and tungsten, are used for high-speed, heavy-duty, high temperature cutting tools, and for dies.

Cobalt is also used in other magnetic steels and stainless steels, and in alloys used in jet turbines and gas turbine generators. The metal is used in electroplating because of its appearance, hardness, and resistance to oxidation.

Cobalt salts have been used for centuries to produce brilliant and permanent blue colors in porcelain, glass, pottery, tiles, and enamels. It is the principal ingredient in Sevre's and Thenard's blue. A solution of the chloride is used as a sympathetic ink. Cobalt carefully used in the form of the chloride, sulfate, acetate, or nitrate has been found effective in correcting a certain mineral deficiency disease in animals.

Soils should contain 0.13 to 0.30 ppm of cobalt for proper animal nutrition.

Isotopes

Cobalt-60, an artificial isotope, is an important gamma ray source, and is extensively used as a tracer and a radiotherapeutic agent.

General Info

AtomicNumber
27
Symbol
Co
Name
Cobalt

Atomic Info

Appearance
AtomicWeight
58.933195(5)
Color
F090A0
ElectronicConfiguration
[Ar] 3d7 4s2
ElectronegativityInPauling
1.88
AtomicRadiusInPM
126
IonRadiusInPM
74.5 (+2*)
VanDerWaalsRadiusInPM
IEinKJmol
760
EAinKJmol
-64
OxidationStates
-1, 1, 2, 3, 4, 5
StandardState
solid
BondingType
metallic
MeltingPoint
1768
BoilingPoint
3200
Density
8.9
State
Transition metal
DiscoveredYear
Ancient