Manganese(II) sulfate

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 260,000 tonnes of manganese(II) sulfate were produced worldwide in 2005. It is the precursor to manganese metal and many other chemical compounds. Manganese-deficient soil is remediated with this salt.[1]

Manganese(II) sulfate

Manganese(II) sulfate monohydrate

Manganese(II) sulfate tetrahydrate
Names
IUPAC name
Manganese(II) sulfate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.029.172
EC Number
  • 232-089-9
RTECS number
  • OP1050000 (anhydrous)
    OP0893500 (tetrahydrate)
UNII
  • InChI=1S/Mn.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 checkY
    Key: SQQMAOCOWKFBNP-UHFFFAOYSA-L checkY
  • InChI=1/Mn.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2
    Key: SQQMAOCOWKFBNP-NUQVWONBAV
  • [Mn+2].[O-]S([O-])(=O)=O
Properties
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/cm3 (anhydrous)
2.95 g/cm3 (monohydrate)
2.107 g/cm3 (tetrahydrate)
Melting point 710 °C (1,310 °F; 983 K) (anhydrous)
27 °C (tetrahydrate)
Boiling point 850 °C (1,560 °F; 1,120 K) (anhydrous)
52 g/100 mL (5 °C)
70 g/100 mL (70 °C)
Solubility Very slightly soluble in methanol
insoluble in ether and ethanol.
1.3660×10−2 cm3/mol
Structure
orthogonal (anhydrous)
monoclinic (monohydrate)
monoclinic (tetrahydrate)
Hazards
GHS labelling:
GHS08: Health hazardGHS09: Environmental hazard
Warning
H373, H411
P260, P273, P314, P391, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamond
1
0
1
Safety data sheet (SDS) ICSC 0290
Related compounds
Other cations
 Chromium(III) 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 verify (what is checkY☒N ?)
Infobox references

Structure
Coordination sphere for Mn and S in the monohydrate. The O6 coordination sphere is provided by four separate sulfate groups and a pair of mutually trans bridging aquo ligands.[2]

Like many metal sulfates, manganese sulfate forms a variety of hydrates: monohydrate, tetrahydrate, pentahydrate, and heptahydrate. All of these salts dissolve in water to give faintly pink solutions of the aquo complex [Mn(H2O)6]2+. The structure of MnSO4·H2O has been determined by X-ray crystallography (see figure). The tetrahydrate also features Mn(II) in an O6 coordination sphere provided by bridging two sulfate anions and four aquo ligands.[3]

Applications and production

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:[4]

MnO2 + SO2 + H2O → MnSO4(H2O)

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

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

Electrolysis

Electrolysis of manganese sulfate reverses the above reaction yielding 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]

Natural occurrence

Manganese(II) sulfate minerals are very rare in nature and always occur as hydrates. The monohydrate is called szmikite; the tetrahydrate is called ilesite; the pentahydrate is called jōkokuite; the hexahydrate, the most rare, is called chvaleticeite; and the heptahydrate is called mallardite.[5]

References
  1. Reidies, Arno H. "Manganese Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH.
  2. Wildner, M.; Giester, G. (1991). "The Crystal Structures of Kieserite-type Compounds. I. Crystal Structures of Me(II)SO4*H2O (Me = Mn, Fe, Co, Ni, Zn) (English translation)". Neues Jahrbuch für Mineralogie - Monatshefte: 296-p306.
  3. Held, Peter; Bohatý, Ladislav (2002). "Manganese(II) Sulfate Tetrahydrate (Ilesite)". Acta Crystallographica Section E. 58 (12): i121–i123. doi:10.1107/S1600536802020962. S2CID 62599961.
  4. John R. Ruhoff (1936). "n-Heptanoic acid". Organic Syntheses. 16: 39. doi:10.15227/orgsyn.016.0039.
  5. "Home". mindat.org.
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