Manganese(II) sulfate

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Manganese(II) sulfate
Manganese(II) sulfate close-up.jpg
Manganese(II) sulfate monohydrate
Manganese(II)-sulfate-tetrahydrate-sample.jpg
Manganese(II) sulfate tetrahydrate
Identifiers
CAS number 7785-87-7 YesY
10034-96-5 (monohydrate)
10101-68-5 (tetrahydrate)
PubChem 24580
ChemSpider 22984 YesY
UNII IGA15S9H40 YesY
EC number 232-089-9
ChEMBL CHEMBL1200557 N
RTECS number OP1050000 (anhydrous)
OP0893500 (tetrahydrate)
Jmol-3D images Image 1
Properties
Molecular formula MnSO4
Molar mass 151.001 g/mol (anhydrous)
169.02 g/mol (monohydrate)
223.07 g/mol (tetrahydrate)
277.11 g/mol (heptahydrate)
Appearance white crystals (anhydrous)
pale pink solid (hydrates)
Density 3.25 g/cm 3 (anhydrous)
2.95 g/cm3 (monohydrate)
2.107 g/cm3 (tetrahydrate)
Melting point 710 °C (anhydrous)
27 °C (tetrahydrate)
Boiling point 850 °C (anhydrous)
Solubility in water 52 g/100 mL (5 °C)
70 g/100 mL (7 °C)
Solubility soluble in alcohol
insoluble in ether
Structure
Crystal structure orthogonal (anhydrous)
monoclinic (monohydrate)
monoclinic (tetrahydrate)
Hazards
MSDS ICSC 0290
EU Index 025-003-00-4
EU classification Harmful (Xn)
Dangerous for the environment (N)
R-phrases R48/20/22, R51/53
S-phrases (S2), S22, S61
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Other cations Chromium(III) sulfate
Iron(II) sulfate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Manganese(II) sulfate usually refers to the inorganic compound with the formula MnSO4(H2O). This pale pink deliquescent solid is a commercially significant manganese(II) salt. Approximately 260 thousand tonnes of manganese(II) sulfate were produced worldwide in 2005. It is the precursor to manganese metal and many other chemical compounds. Mn-deficient soil is remediated with this salt.[1]

Structure[edit]

Like many metal sulfates, manganese sulfate forms a variety of hydrates: monohydrate, tetrahydrate, pentahydrate, and heptahydrate. The monohydrate is most common. All of these salts dissolve to give faintly pink solutions of the aquo complex [Mn(H2O)6]2+. The pale pink colour of Mn(II) salts is highly characteristic.

Applications and production[edit]

Typically, manganese ores are purified by their conversion to manganese(II) sulfate. Treatment of aqueous solutions of the sulfate with sodium carbonate leads to precipitation of manganese carbonate, which can be calcined to give the oxides MnOx. In the laboratory, manganese sulfate can be made by treating manganese dioxide with sulfur dioxide:[2]

MnO2 + SO2 → MnSO4

It can also be made by mixing potassium permanganate with sodium hydrogen sulfate and hydrogen peroxide.

H2O + KMnO4 + NaHSO4 + H2O2 → MnSO4 + MnSO2

Manganese sulfate is a by-product of various industrially significant oxidations that use manganese dioxide, including the manufacture of hydroquinone and anisaldehyde.[1]

Electrolysis of manganese sulfate yields manganese dioxide, which is called EMD for electrolytic manganese dioxide. Alternatively oxidation of manganese sulfate with potassium permanganate yields the so-called chemical manganese dioxide (CMD). These materials, especially EMD, are used in dry-cell batteries.[1]

References[edit]

  1. ^ a b c Arno H. Reidies "Manganese Compounds" Ullmann's Encyclopedia of Chemical Technology 2007; Wiley-VCH, Weinheim. doi:10.1002/14356007.a16_123
  2. ^ John R. Ruhoff (1943), "n-Heptanoic acid", Org. Synth. ; Coll. Vol. 2: 315