Cobalt(II) chloride

Cobalt(II) chloride

Anhydrous Hexahydrate
Structure of anhydrous compound
Structure of hexahydrate
Names
IUPAC name Cobalt(II) chloride
Other names Cobaltous chloride Cobalt dichloride Muriate of cobalt
Identifiers
CAS Number	7646-79-9 Y 16544-92-6 (dihydrate) N 7791-13-1 (hexahydrate) N
3D model (Jmol)	Interactive image
ChEBI	CHEBI:35696 Y
ChemSpider	22708 Y
ECHA InfoCard	100.028.718
EC Number	231-589-4
PubChem	3032536
RTECS number	GF9800000
UNII	EVS87XF13W Y
UN number	3288
InChI InChI=1S/2ClH.Co/h2*1H;/q;;+2/p-2 Y Key: GVPFVAHMJGGAJG-UHFFFAOYSA-L Y InChI=1/2ClH.Co/h2*1H;/q;;+2/p-2 Key: GVPFVAHMJGGAJG-NUQVWONBAU
SMILES Cl[Co]Cl
Properties
Chemical formula	CoCl2
Molar mass	129.839 g/mol (anhydrous) 165.87 g/mol (dihydrate) 237.93 g/mol (hexahydrate)
Appearance	blue crystals (anhydrous) violet-blue (dihydrate) rose red crystals (hexahydrate)
Density	3.356 g/cm3 (anhydrous) 2.477 g/cm3 (dihydrate) 1.924 g/cm3 (hexahydrate)
Melting point	735 °C (1,355 °F; 1,008 K) (anhydrous) 140 °C (monohydrate) 100 °C (dihydrate) 86 °C (hexahydrate)
Boiling point	1,049 °C (1,920 °F; 1,322 K)
Solubility in water	43.6 g/100 mL (0 °C) 45 g/100 mL (7 °C) 52.9 g/100 mL (20 °C) 105 g/100 mL (96 °C)
Solubility	38.5 g/100 mL (methanol) 8.6 g/100 mL (acetone) soluble in ethanol, ether, pyridine, glycerol
Magnetic susceptibility (χ)	+12,660·10−6 cm3/mol
Structure
Crystal structure	CdCl2 structure
Coordination geometry	hexagonal (anhydrous) monoclinic (dihydrate) Octahedral (hexahydrate)
Hazards
Safety data sheet	ICSC 0783
EU classification (DSD)	Toxic (T) Carc. Cat. 2 Dangerous for the environment (N)
R-phrases	R49, R60, R22, R42/43, R68, R50/53
S-phrases	S53, S45, S60, S61
NFPA 704	0 2 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	80 mg/kg (rat, oral)
Related compounds
Other anions	Cobalt(II) fluoride Cobalt(II) bromide Cobalt(II) iodide
Other cations	Rhodium(III) chloride Iridium(III) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Cobalt(II) chloride is an inorganic compound of cobalt and chlorine, with the formula CoCl₂. It is usually supplied as the hexahydrate CoCl₂·6H₂O, which is one of the most commonly used cobalt compounds in the lab.

The hexahydrate is purple, whereas the anhydrous form is sky blue. Because of the ease of the hydration/dehydration reaction, and the resulting color change, cobalt chloride is used as an indicator for water in desiccants.

Niche uses of cobalt chloride include its role in organic synthesis and electroplating objects with cobalt metal.

Cobalt chloride has been classified as a substance of very high concern by the European Chemicals Agency as it is a suspected carcinogen.

Aqueous solutions of both CoCl₂ and the hydrate contain the species [Co(H₂O)₆]²⁺. They also contain chloride ions. In the solid state CoCl₂·6H₂O consists of the molecule trans-[CoCl₂(H₂O)₄] and two molecules of water of crystallization. This species dissolves readily in water and alcohol. Concentrated aqueous solutions are red at room temperature but become blue at higher temperatures. CoCl₂·6H₂O is deliquescent, and the anhydrous salt CoCl₂ is hygroscopic, readily converting to the hydrate.

Hydrated cobalt chloride is prepared from cobalt(II) hydroxide or cobalt(II) carbonate and hydrochloric acid: