Cobalt(II) bromide

Cobalt(II) bromide

Identifiers
CAS Number	7789-43-7 Y
3D model (Jmol)	Interactive image
ChemSpider	23012 Y
ECHA InfoCard	100.029.242
PubChem CID	24610
RTECS number	GF9595000
InChI InChI=1S/2BrH.Co/h2*1H;/q;;+2/p-2 Y Key: BZRRQSJJPUGBAA-UHFFFAOYSA-L Y InChI=1/2BrH.Co/h2*1H;/q;;+2/p-2 Key: BZRRQSJJPUGBAA-NUQVWONBAJ
SMILES [Co](Br)Br
Properties
Chemical formula	CoBr2, CoBr2.6H2O, CoBr2.2H2O
Molar mass	218.7412 g/mol (anhydrous) 326.74 g/mol (hexahydrate)
Appearance	Bright green crystals (anhydrous) Red-purple crystals (hexahydrate)
Density	4.909 g/cm3 (anhydrous) 2.46 g/cm3 (hexahydrate)
Melting point	678 °C (1,252 °F; 951 K) (anhydrous) 47 °C (hexahydrate)
Solubility in water	anhydrous: 66.7 g/100 mL (59 °C) 68.1 g/100 mL (97 °C) hexahydrate: 113.2 g/100 mL (20 °C)
Solubility	77.1 g/100 mL (ethanol, 20 °C) 58.6 g/100 mL (methanol, 30 °C) soluble in methyl acetate, ether, alcohol, acetone
Magnetic susceptibility (χ)	+13000·10−6 cm3/mol
Structure
Crystal structure	Rhombohedral, hP3, SpaceGroup = P-3m1, No. 164
Coordination geometry	octahedral
Hazards
Safety data sheet	Fisher Scientific
R-phrases (outdated)	R36, R37, R38
S-phrases (outdated)	S26, S37, S39, S45, S28A
NFPA 704	0 2 1
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	406 mg/kg (oral, rat)
Related compounds
Other anions	cobalt(II) fluoride cobalt(II) chloride cobalt(II) iodide
Other cations	iron(II) bromide nickel(II) bromide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Cobalt(II) bromide (CoBr₂) is an inorganic compound. It is a red solid that is soluble in water, used primarily as a catalyst in some processes.

When anhydrous, cobalt(II) bromide appears as green crystals. The hexahydrate loses four waters of crystallization molecules at 100 °C forming the dihydrate:

Further heating to 130 °C produces the anhydrous form:

The anhydrous form melts at 678 °C. At higher temperatures, cobalt(II) bromide reacts with oxygen, forming cobalt(II,III) oxide and bromine vapor.

Cobalt(II) bromide can be prepared as a hydrate by the reaction of cobalt hydroxide with hydrobromic acid:

Anhydrous cobalt(II) bromide may be prepared through the direct reaction of elemental cobalt and liquid bromine.

The classical coordination compound bromopentaamminecobalt(III) bromide is prepared by oxidation of a solution of cobalt(II) bromide in aqueous ammonia.

Triphenylphosphine complexes of cobalt(II) bromide have been used as a catalysts in organic synthesis.

Exposure to large amounts of cobalt(II) can cause cobalt poisoning. Bromide is also mildly toxic.