What Is Cobalt Oxide?
Cobalt oxide, also recognized as tricobalt tetroxide, appears as a grayish-black or black powder. It has a chemical formula of Co3O4, a molecular weight of 240.80, and a CAS number of 1308-06-1. With a melting point of 895°C, it is insoluble in water but soluble in hydrochloric acid and concentrated alkali.
This compound is regulated under various laws and regulations due to its hazardous nature, including the PRTR Law and the Air Pollution Control Law.
Uses of Cobalt Oxide
As an oxidizer and catalyst, cobalt oxide is crucial for producing cobalt salts and serves as a pigment in ceramics and glass. It is instrumental in manufacturing cathode materials for lithium batteries, enamel, and as an additive in animal feed.
Properties of Cobalt Oxide
Cobalt oxide compounds vary by cobalt’s oxidation state, including cobalt (II) oxide, cobalt (III) oxide, and cobalt (II, III) oxide, with CoIICoIII2O4 representing the mixed-valence compound.
1. Cobalt (II) Oxide
With the formula CoO, cobalt (II) oxide is a red to yellow-green crystal or black to gray powder, used in blue glazes and for synthesizing cobalt (II) salts. It forms by reacting cobalt with water vapor or decomposing cobalt oxide (II, III) at high temperatures.
2. Cobalt (III) Oxide
This blackish-brown powder, Co2O3, forms by reacting cobalt (II) nitrate with sodium hypochlorite, used as a catalyst and oxidizing agent.
Structure of Cobalt Oxide
The tricobalt tetroxide, or cobalt (II, III) oxide, exhibits a spinel-type structure, with Co2+ ions in tetrahedral sites and Co3+ ions in octahedral sites of the oxide ion lattice.
Other Information on Cobalt Oxide
1. Synthesis of Cobalt (II, III) Oxide
Produced by heating cobalt (II) oxide in air, it transitions to more stable forms at temperatures above 900°C.
2. Uses of Cobalt (II) Oxide
Historically significant as a pigment in ceramics, cobalt (II) oxide creates the deep blue known as cobalt blue. It is also essential in producing magnetic and battery materials and as a catalyst in oxidation reactions.