Cobalt chloride (CoCl2) is a toxic, colorless, volatile and hygroscopic compound. It is soluble in water, ethanol, acetone and ether. It is a common precursor to other cobalt compounds, such as cobaltocene and tetralykl. CoCl2 is used in industrial applications including electroplating and surface treating metal. It is also a popular research tool in the formation of hydrogen, oxidation reactions, and as an indicator for water in silica gel desiccants.
The hydrate of CoCl2, CoCl2*6H2O, is deep rose in color. It is a metastable crystal and readily converts to the anhydrous salt by heating. It is deliquescent and has a high melting point. It is a useful cobalt(II) indicator for water in silica gel desiccants. It is also used as a coating agent, an indicator for paint and glass ceramic colorants, a dye and drying agent, an absorbent for military poison gas and ammonia, and a beer foam stabilizer. It is also a catalyst in Grignard reactions and used in the manufacture of vitamin B12.
Cobalt chloride hexahydrate is toxic, corrosive and reactive. It is irritating to skin and eyes. If inhaled, it may cause an allergic reaction and bronchial asthma. The production of CoCl2 requires the use of respirators to prevent inhalation of dust, and the workplace should be well ventilated. It is also a known carcinogen. Inhalation may cause loss of appetite, vomiting, diarrhea, edema, facial and limb redness, and dermatitis in the mouth. When mixed with acetone, it forms the highly toxic compound, cobalt acetate.