Nickel(II) sulfate

Nickel(II) sulfate

Anhydrous Hexahydrate
Names
IUPAC name Nickel(II) sulfate
Other names Nickelous sulfate
Identifiers
CAS Number	7786-81-4 (anhydrous) Y 10101-97-0 (hexahydrate) N 10101-98-1 (heptahydrate) N
3D model (Jmol)	Interactive image
ChEBI	CHEBI:53001 Y
ChemSpider	22989 Y
ECHA InfoCard	100.029.186
EC Number	232-104-9
PubChem	24586
RTECS number	QR9600000
UNII	4FLT4T3WUN Y
InChI InChI=1S/Ni.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 Y Key: LGQLOGILCSXPEA-UHFFFAOYSA-L Y InChI=1/Ni.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 Key: LGQLOGILCSXPEA-NUQVWONBAG
SMILES [Ni+2].[O-]S([O-])(=O)=O
Properties
Chemical formula	NiSO4
Molar mass	154.75 g/mol (anhydrous) 262.85 g/mol (hexahydrate) 280.86 g/mol (heptahydrate)
Appearance	yellow solid (anhydrous) blue crystals (hexahydrate) green-blue crystals (heptahydrate)
Odor	odorless
Density	4.01 g/cm3 (anhydrous) 2.07 g/cm3 (hexahydrate) 1.948 g/cm3 (heptahydrate)
Melting point	> 100 °C (anhydrous) 53 °C (hexahydrate)
Boiling point	840 °C (1,540 °F; 1,110 K) (anhydrous, decomposes) 100 °C (hexahydrate, decomposes)
Solubility in water	65 g/100 mL (20 °C) 77.5 g/100 mL (30 °C) (heptahydrate)
Solubility	anhydrous insoluble in ethanol, ether, acetone hexahydrate very soluble in ethanol, ammonia heptahydrate soluble in alcohol
Acidity (pKa)	4.5 (hexahydrate)
Magnetic susceptibility (χ)	+4005.0·10−6 cm3/mol
Refractive index (nD)	1.511 (hexahydrate) 1.467 (heptahydrate)
Structure
Crystal structure	cubic (anhydrous) tetragonal (hexahydrate) rhombohedral (hexahydrate)
Hazards
Safety data sheet	External MSDS
EU classification (DSD)	Carc. Cat. 1 Muta. Cat. 3 Repr. Cat. 2 Toxic (T) Harmful (Xn) Irritant (Xi) Dangerous for the environment (N)
R-phrases	R49, R61, R20/22, 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)	264 mg/kg
Related compounds
Other cations	Cobalt(II) sulfate Copper(II) sulfate Iron(II) sulfate
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) sulfate, or just nickel sulfate, usually refers to the inorganic compound with the formula NiSO₄(H₂O)₆. This highly soluble blue-coloured salt is a common source of the Ni²⁺ion for electroplating.

Approximately 40,000 tonnes were produced in 2005. It is mainly used for electroplating of nickel.

In 2005–06, nickel sulfate was the top allergen in patch tests (19.0%).

At least seven sulfate salts of nickel(II) are known. These salts differ in terms of their hydration or crystal habit.

The common tetragonal hexahydrate crystallizes from aqueous solution between 30.7 and 53.8 °C. Below these temperatures, a heptahydrate crystallises, and above these temperatures an orthorhombic hexahydrate forms. The yellow anhydrous form, NiSO₄, is a high melting solid that is rarely encountered in the laboratory. This material is produced by heating the hydrates above 330 °C. It decomposes at still higher temperatures to nickel oxide.

X-ray crystallography measurements show that NiSO₄·6H₂O consists of the octahedral [Ni(H₂O)₆]²⁺ ions. These ions in turn are hydrogen bonded to sulfate ions. Dissolution of the salt in water gives solutions containing the aquo complex [Ni(H₂O)₆]²⁺.

All nickel sulfates are paramagnetic.

The salt is usually obtained as a by-product of copper refining. It is also produced by dissolution of nickel metal or nickel oxides in sulfuric acid.

Aqueous solutions of nickel sulfate reacts with sodium carbonate to precipitate nickel carbonate, a precursor to nickel-based catalysts and pigments. Addition of ammonium sulfate to concentrated aqueous solutions of nickel sulfate precipitates Ni(NH₄)₂(SO₄)₂·6H₂O. This blue-coloured solid is analogous to Mohr's salt, Fe(NH₄)₂(SO₄)₂·6H₂O.