Cobalt(II) oxide

Cobalt(II) oxide, also known as cobaltous oxide, is a chemical compound. Its chemical formula is CoO. It contains cobalt in its +2 oxidation state as an ion. It also contains oxide. It can be green or red crystals. It can also be a grey or brown powder. 

Preparation
Cobalt(II) chloride reacts with a base to get cobalt(II) hydroxide. Then the cobalt(II) hydroxide is heated to make cobalt(II) oxide. The reactions are written below:
 CoCl2 + 2 NaOH → 2 NaCl + Co(OH)2
 Co(OH)2 → CoO + H2O

Use
It can react with acids to make salts containing cobalt. It is used to make blue glass.

Related pages
Cobalt(II) sulfate
Cobalt(III) oxide

Category:Cobalt compounds
Category:Oxides