Nickel(II) chloride

Nickel(II) chloride

Hexahydrate
Anhydrous
Names
IUPAC name Nickel(II) chloride
Other names Nickelous chloride, nickel(II) salt of hydrochloric acid
Identifiers
CAS Number	7718-54-9 Y 7791-20-0 (hexahydrate) N
3D model (Jmol)	Interactive image
ChEBI	CHEBI:34887 Y
ChemSpider	22796 Y
ECHA InfoCard	100.108.731
EC Number	231-743-0
KEGG	C14711 Y
PubChem	24385
RTECS number	QR6480000
InChI InChI=1S/2ClH.Ni/h2*1H;/q;;+2/p-2 Y Key: QMMRZOWCJAIUJA-UHFFFAOYSA-L Y InChI=1/2ClH.Ni/h2*1H;/q;;+2/p-2 Key: QMMRZOWCJAIUJA-NUQVWONBAR
SMILES Cl[Ni]Cl
Properties
Chemical formula	NiCl2
Molar mass	129.5994 g/mol (anhydrous) 237.69 g/mol (hexahydrate)
Appearance	yellow-brown crystals deliquescent (anhydrous) green crystals (hexahydrate)
Odor	odorless
Density	3.55 g/cm3 (anhydrous) 1.92 g/cm3 (hexahydrate)
Melting point	1,001 °C (1,834 °F; 1,274 K) (anhydrous) 140 °C (hexahydrate)
Solubility in water	anhydrous 67.5 g/100 mL (25 °C) 87.6 g/100 mL (100 °C) hexahydrate 123.8 g/100 mL (25 °C) 160.7 g/100 mL (100 °C)
Solubility	0.8 g/100 mL (hydrazine) soluble in ethylene glycol, ethanol, ammonium hydroxide insoluble in ammonia, nitric acid
Acidity (pKa)	4 (hexahydrate)
Magnetic susceptibility (χ)	+6145.0·10−6 cm3/mol
Structure
Crystal structure	Monoclinic
Coordination geometry	octahedral at Ni
Thermochemistry
Std molar entropy (So298)	107 J·mol−1·K−1
Std enthalpy of formation (ΔfHo298)	−316 kJ·mol−1
Hazards
Safety data sheet	Fischer Scientific
EU classification (DSD)	Carc. Cat. 1 Muta. Cat. 3 Repr. Cat. 2 Toxic (T) Irritant (Xi) Dangerous for the environment (N)
R-phrases	R49, R61, R23/25, R38, R42/43, R48/23, 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)	105 mg/kg (rat, oral)
Related compounds
Other anions	Nickel(II) fluoride Nickel(II) bromide Nickel(II) iodide
Other cations	Palladium(II) chloride Platinum(II) chloride Platinum(II,IV) chloride Platinum(IV) chloride
Related compounds	Cobalt(II) chloride Copper(II) 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

Nickel(II) chloride (or just nickel chloride), is the chemical compound NiCl₂. The anhydrous salt is yellow, but the more familiar hydrate NiCl₂·6H₂O is green. Nickel(II) chloride, in various forms, is the most important source of nickel for chemical synthesis. The nickel chlorides are deliquescent, absorbing moisture from the air to form a solution. Nickel salts are carcinogenic.

The largest scale production of nickel chloride involves the extraction with hydrochloric acid of nickel matte and residues obtained from roasting refining nickel-containing ores.

Nickel chloride is not usually prepared in the laboratory because it is inexpensive and has a long shelf-life. Heating the hexahydrate in the range 66-133.°C gives the yellowish dihydrate, NiCl₂·2H₂O. The hydrates convert to the anhydrous form upon heating in thionyl chloride or by heating under a stream of HCl gas. Simply heating the hydrates does not afford the anhydrous dichloride.

The dehydration is accompanied by a color change from green to yellow.

In case one needs a pure compound without presence of cobalt, nickel chloride can be obtained cautiously heating hexammine nickel chloride:

NiCl₂ adopts the CdCl₂ structure. In this motif, each Ni²⁺ center is coordinated to six Cl⁻ centers, and each chloride is bonded to three Ni(II) centers. In NiCl₂ the Ni-Cl bonds have "ionic character". Yellow NiBr₂ and black NiI₂ adopt similar structures, but with a different packing of the halides, adopting the CdI₂ motif.

In contrast, NiCl₂·6H₂O consists of separated trans-[NiCl₂(H₂O)₄] molecules linked more weakly to adjacent water molecules. Only four of the six water molecules in the formula are bound to the nickel, and the remaining two are water of crystallisation.Cobalt(II) chloride hexahydrate has a similar structure. The hexahydrate occurs in nature as the very rare mineral nickelbischofite.