Molar mass 154.996 g/mol Density 3.71 g/cm³ | Formula CoSO4 Melting point 735 °C | |
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Appearance reddish crystalline (anhydrous, monohydrate); pink salt (hexahydrate) | ||
Cobalt(II) sulfate is any of the inorganic compounds with the formula CoSO4(H2O)x. Usually cobalt sulfate refers to the hydrate CoSO4.7H2O, which is one of the most commonly available salts of cobalt.
Contents
Properties, preparation, and structure
Cobalt(II) sulfate heptahydrate appears as red monoclinic crystals that liquify around 100 °C and become anhydrous at 250 °C. It is soluble in water, slightly soluble in ethanol, and especially soluble in methanol. The salts are paramagnetic.
It forms by the reaction of metallic cobalt, its oxide, hydroxide, or carbonate with aqueous sulfuric acid.
The hexahydrate is a metal aquo complex consisting of octahedral [Co(H2O)6]2+ ions associated with sulfate anions.
Uses
Cobalt is obtained from ores via the sulfate in many cases.
Hydrated cobalt(II) sulfate is used in the preparation of pigments, as well as in the manufacture of other cobalt salts. Cobalt pigment is used in porcelains and glass. Cobalt(II) sulfate is used in storage batteries and electroplating baths, sympathetic inks, and as an additive to soils and animal feeds. For these purposes, the cobalt sulfate is produced by treating cobalt oxide with sulfuric acid.
Health issues
Cobalt is essential for most higher forms of life, but more than a few milligrams each day is harmful. Rarely have poisonings resulted from cobalt compounds. Upon inhalation of salts, there is some evidence for carcinogenicity.