Cobalt(II) hydroxide or cobaltous hydroxide is the inorganic compound with the formula Co(OH)2, consisting of divalent cobalt cations Co2+ and hydroxide anions HO−. The pure compound, often called the "beta form" (β-Co(OH)2) is a pink solid insoluble in water.
Molar mass:92.948 g/mol
Appearance:rose-red powder or bluish-green powder
Melting point:168 °C (334 °F; 441 K) (decomposes)
Solubility in water:3.20 mg/L
Solubility product (Ksp):1.0×10−15
Solubility:soluble in acids, ammonia; insoluble in dilute alkalis
Cobalt(II) hydroxide is used as a drying agent for paints and varnishes. It acts as an aid to dry the lithographic inks and catalyst in the preparation of battery electrode impregnating solutions. It is also involved in the synthesis of other cobalt compounds.