Cobalt(II) oxide

Cobalt(II) oxide is a blackish gray powder used extensively in the ceramics industry as an additive to create blue colored glazes and enamels as well as in the chemical production industry for producing cobalt(II) salts.

Cobalt(II) oxide is a product of Cobalt(III) oxide decomposing at 895 °C through the reaction:

2 Co₃O_4(s) → 6 CoO_(s) + O_2(g)

Ceramics

Cobalt(II) Oxide has been used for centuries as a coloring agent on kiln fired ceramic glazes, the earliest examples go back to 12th century German pottery. The additive produces a deep shade of blue once it has been fired in a kiln that is often referred to as cobalt blue.

Industrial Uses

As stated earlier, cobalt(II) oxide is used in the production of cobalt(II) salts such as CoCl₂ and Co(NO₃)₂.

References

1. http://www.ceramicstoday.com/articles/zamek_cobalt.htm