Nickel(II) sulfate

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Nickel(II) sulfate
Nickel sulfate anh.jpg
Anhydrous
Nickel sulfate hydrate.jpg
Hexahydrate
N9(H2O)6SO4.png
Identifiers
CAS number 7786-81-4 YesY, (anhydrous)
10101-97-0 (hexahydrate)
10101-98-1 (heptahydrate)
PubChem 24586
ChemSpider 22989 YesY
UNII 4FLT4T3WUN YesY
EC number 232-104-9
ChEBI CHEBI:53001 YesY
RTECS number QR9600000
Jmol-3D images Image 1
Properties
Molecular 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 (anhydrous, decomp)
100 °C (hexahydrate, decomp)
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)
Refractive index (nD) 1.511 (hexahydrate)
1.467 (heptahydrate)
Structure
Crystal structure cubic (anhydrous)
tetragonal (hexahydrate)
rhombohedral (hexahydrate)
Hazards
MSDS External MSDS
EU Index 028-009-00-5
EU classification 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
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
LD50 264 mg/kg
Related compounds
Other cations Cobalt(II) sulfate
Copper(II) sulfate
Iron(II) sulfate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
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.[1]

Structures[edit]

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 produced by heating the hydrates above 330 °C. It decomposes at still higher temperatures to nickel oxide.[1]

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.[2] Dissolution of the salt in water gives solutions containing the aquo complex [Ni(H2O)6]2+.

All nickel sulfates are paramagnetic.

Production, applications, and coordination chemistry[edit]

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.[3] 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.[1]

Nickel sulfate is used in the laboratory. Columns used in polyhistidine-tagging, useful in biochemistry and molecular biology, are regenerated with nickel sulfate. Aqueous solutions of NiSO4·6H2O and related hydrates react with ammonia to give [Ni(NH3)6]SO4 and with ethylenediamine to give [Ni(H2NCH2CH2NH2)3]SO4. The latter is occasionally used as a calibrant for magnetic susceptibility measurements because it has no tendency to hydrate.

Natural occurrence[edit]

Nickel sulfate occurs as the rare mineral retgersite, which is a hexahydrate. The second hexahydrate is known as nickelhexahydrite(Ni,Mg,Fe)SO4·6H2O. The heptahydrate, which is relatively unstable in air, occurs as morenosite. The monohydrate occurs as very rare mineral dwornikite (Ni,Fe)SO4·H2O.

Safety[edit]

In 2005–06, nickel sulfate was the top allergen in patch tests (19.0%).[4]

Nickel salts are carcinogenic and irritate the skin.

References[edit]

  1. ^ a b c K. Lascelles, L. G. Morgan, D. Nicholls, D. Beyersmann “Nickel Compounds” in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. Vol. A17 p. 235 doi:10.1002/14356007.a17_235.pub2.
  2. ^ Wells, A. F. (1984). Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
  3. ^ H. B. W. Patterson, "Catalysts" in Hydrogenation of Fats and Oils G. R. List and J. W. KIng, Eds., 1994, AOCS Press, Urbana.
  4. ^ Zug KA, Warshaw EM, Fowler JF Jr, Maibach HI, Belsito DL, Pratt MD, Sasseville D, Storrs FJ, Taylor JS, Mathias CG, Deleo VA, Rietschel RL, Marks J. Patch-test results of the North American Contact Dermatitis Group 2005–2006. Dermatitis. 2009 May–Jun;20(3):149-60.

External links[edit]