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
CAS Number	7785-87-7^Y 10034-96-5 (monohydrate)^N 10101-68-5 (tetrahydrate)^N
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL1200557^N
ChemSpider	22984^Y
ECHA InfoCard	100.029.172
EC Number	232-089-9
PubChem CID	24580
RTECS number	OP1050000 (anhydrous) OP0893500 (tetrahydrate)
UNII	IGA15S9H40^Y
CompTox Dashboard (EPA)	DTXSID9044160
InChI InChI=1S/Mn.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2^Y Key: SQQMAOCOWKFBNP-UHFFFAOYSA-L^Y InChI=1/Mn.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 Key: SQQMAOCOWKFBNP-NUQVWONBAV
SMILES [Mn+2].[O-]S([O-])(=O)=O
Properties
Chemical 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/cm^3 (monohydrate) 2.107 g/cm^3 (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)
Solubility in water	52 g/100 mL (5 °C) 70 g/100 mL (70 °C)
Solubility	Very slightly soluble in methanol insoluble in ether and ethanol.
Magnetic susceptibility (χ)	1.3660×10^−2 cm^3/mol
Structure
Crystal structure	orthogonal (anhydrous) monoclinic (monohydrate) monoclinic (tetrahydrate)
Hazards
Safety data sheet	ICSC 0290
EU classification (DSD) (outdated)	Harmful (Xn) Dangerous for the environment (N)
R-phrases (outdated)	R48/20/22, R51/53
S-phrases (outdated)	(S2), S22, S61
NFPA 704 (fire diamond)	0 1 1
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 ^YN ?)
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]

The structure of MnSO₄·H₂O has been determined by X-ray crystallography. Like many metal sulfates, manganese sulfate forms a variety of hydrates: monohydrate, tetrahydrate, pentahydrate, and heptahydrate. All of these salts dissolve to give faintly pink solutions of the aquo complex [Mn(H₂O)₆]²⁺.

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 MnO_x. In the laboratory, manganese sulfate can be made by treating manganese dioxide with sulfur dioxide:[3]

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 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]

Natural occurrence

Manganese(II) sulfate minerals are very rare in nature and always occur as hydrates. The monohydrate is called szmikite; tetrahydrate = ilesite; hexahydrate (the most rare) = chvaleticeite; pentahydrate = jōkokuite; heptahydrate = mallardite.[4]

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 fuer Mineralogie, Monatshefte: 296-p306.CS1 maint: multiple names: authors list (link)
3. John R. Ruhoff (1936). "n-Heptanoic acid". 16: 39. doi:10.15227/orgsyn.016.0039. Cite journal requires |journal= (help)
4. http://www.mindat.org