3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||74.9326 g/mol|
|Appearance||olive or gray powder|
|Density||6.45 g/cm3 |
|Melting point||1,933 °C (3,511 °F; 2,206 K)|
|insoluble in water|
|Fm3m, No. 225|
|H302, H317, H410|
|P260, P280, P284, P301+P310+P330, P304+P340+P310, P342+P311, P403+P233|
|NFPA 704 (fire diamond)|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|Safety data sheet (SDS)||ICSC 1551|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
(what is ?)
Cobalt(II) oxide is an inorganic compound that has been described as an olive-green or gray solid. It is used extensively in the ceramics industry as an additive to create blue-colored glazes and enamels, as well as in the chemical industry for producing cobalt(II) salts. A related material is cobalt(II,III) oxide, a black solid with the formula Co3O4.
CoO crystals adopt the periclase (rock salt) structure with a lattice constant of 4.2615 Å.
It is antiferromagnetic below 16 °C.
Cobalt(II) oxide is prepared by oxidation of cobalt powder with air or by thermal decomposition of cobalt(II) nitrate or the carbonate.
Cobalt(II,III) oxide decomposes to cobalt(II) oxide at 950 °C:
It may also be prepared by precipitating the hydroxide, followed by thermal dehydration:
As can be expected, cobalt(II) oxide reacts with mineral acids to form the corresponding cobalt salts:
Cobalt(II) oxide has for centuries been used as a coloring agent on kiln fired pottery. The additive provides a deep shade of blue named cobalt blue. The band gap (CoO) is around 2.4 eV. It also is used in cobalt blue glass.