Cobalt(II) hydroxide is a chemical compound. Its chemical formula is Co(OH)2. It contains cobalt in its +2 oxidation state as an ion. It also contains hydroxide ions. It is either reddish or bluish. It is made by reacting a strong base with a cobalt(II) salt. Cobalt(II) chloride is normally used. This makes the red form. The blue form is made by reacting ammonium hydroxide with cobalt(II) hydroxide. It turns into cobalt(II) oxide when heated. It is used to dry paints, to make other cobalt compounds, and as a catalyst.