Cobalt(II) oxide

"CoO" redirects here. For other uses, see COO (disambiguation).

Cobalt(II) oxide is an inorganic compound that has been described as an olive-green^[3] or gray^[4] 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.

Cobalt(II) oxide

Cobalt(II) oxide
Names
IUPAC name Cobalt(II) oxide
Other names Cobaltous oxide Cobalt monoxide
Identifiers
CAS Number	1307-96-6 Y
3D model (JSmol)	Interactive image Interactive image
ChemSpider	8117730 Y
ECHA InfoCard	100.013.777
EC Number	215-154-6
PubChem CID	9942118
RTECS number	GG2800000
UNII	V9X9644V7Q Y
UN number	3288
CompTox Dashboard (EPA)	DTXSID6051649
InChI InChI=1S/Co.O/q+2;-2 Y Key: IUYLTEAJCNAMJK-UHFFFAOYSA-N Y InChI=1/Co.O/rCoO/c1-2 Key: IVMYJDGYRUAWML-NNYFCMOLAO InChI=1/Co.O/q+2;-2 Key: IUYLTEAJCNAMJK-UHFFFAOYAY
SMILES [Co]=O [Co+2].[O-2]
Properties
Chemical formula	CoO
Molar mass	74.9326 g/mol
Appearance	olive or gray powder
Odor	odorless
Density	6.45 g/cm3 [1]
Melting point	1,933 °C (3,511 °F; 2,206 K)
Solubility in water	insoluble in water[2]
Magnetic susceptibility (χ)	+4900.0·10−6 cm3/mol
Structure
Crystal structure	cubic, cF8
Space group	Fm3m, No. 225
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H317, H410
Precautionary statements	P260, P280, P284, P301+P310+P330, P304+P340+P310, P342+P311, P403+P233
NFPA 704 (fire diamond)	3 0 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	202 mg/kg
Safety data sheet (SDS)	ICSC 1551
Related compounds
Other anions	Cobalt(II) sulfide Cobalt(II) hydroxide
Other cations	Iron(II) oxide Nickel(II) oxide
Related compounds	Cobalt(II,III) oxide Cobalt(III) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Structure and properties

CoO crystals adopt the periclase (rock salt) structure with a lattice constant of 4.2615 Å.^[5]

It is antiferromagnetic below 289 K.^[6]

Preparation

Cobalt(II) oxide is prepared by oxidation of cobalt powder with air or by thermal decomposition of cobalt(II) nitrate or the carbonate.^[3][4]

Cobalt(II,III) oxide decomposes to cobalt(II) oxide at 950 °C:^[7]

2 Co₃O₄ → 6 CoO + O₂

It may also be prepared by precipitating the hydroxide, followed by thermal dehydration:^{[citation needed]}

CoX₂ + 2 KOH → Co(OH)₂ + 2 KX

Co(OH)₂ → CoO + H₂O

Reactions

As can be expected, cobalt(II) oxide reacts with mineral acids to form the corresponding cobalt salts:^{[citation needed]}

CoO + 2 HX → CoX₂ + H₂O

Applications

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.^{[citation needed]} It also is used in cobalt blue glass.

See also

• Cobalt oxide nanoparticles
• Cobalt
• Cobalt(II,III) oxide