Manganese(II) sulfate

Manganese(II) sulfate

Manganese(II) sulfate heptahydrate crystals
Names
IUPAC name Manganese(II) sulfate
Systematic IUPAC name Manganese(II) sulfate
Other names Manganese sulfate
Identifiers
Jmol-3D images	Image
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 solid (anhydrous) Pink crystalline solid (hydrated)
Odor	Odorless
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 (80.6 °F; 300.15 K) (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 (7 °C)
Solubility	Soluble in ethanol, methanol Insoluble in diethyl ether, toluene
Hazards
Safety data sheet	DoGEE (monohydrate)
Flash point	Non-flammable
Related compounds
Related compounds	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).
Infobox references

Manganese(II) sulfate is the sulfate salt of manganese, with the formula MnSO₄. Although the anhydrous salt is white, its hydrates are pinkish in color.

Properties

Chemical

Manganese(II) sulfate will precipitate as manganese hydroxide when mixed with a strong base, such as sodium hydroxide.

Physical

Manganese sulfate is a pinkish crystalline salt, soluble in water, as well as primary alcohols, though insoluble in aprotic solvents, such as benzene or diethyl ether. It is most often encountered as monohydrate form, though other hydrates, like tetrahydrate, pentahydrate, and heptahydrate also exist.

Availability

Manganese sulfate is sold by various chemical suppliers.

Manganese sulfate monohydrate is available as fertilizer and can be found in many gardening stores, or online.

Preparation

There are a few ways to make manganese(II) sulfate.

One involves the direct reaction of sulfuric acid with manganese metal:

H₂SO₄ + Mn → MnSO₄ + H₂

This reaction however, does not work with manganese dioxide, which is more available that manganese metal. There are a few ways around though:

One way is to react manganese dioxide with oxalic acid and then react the resulting manganese oxalate/carbonate with dilute sulfuric acid.

A more conveninet method involves reacting sulfur dioxide with powdered manganese dioxide. This reaction can be achieved in two ways: bubbling sulfur dioxide in an aqueous suspension of manganese dioxide, while the other involves adding an aq. solution of sulfur dioxide (sold by winemaking suppliers) with manganese dioxide powder. Both reactions are exothermic, so the synthesis must be done outside or in a fumehood, since lots of sulfur dioxide will be produced as side product. After the reaction is complete, the solution must be filtered to remove the insoluble products.

MnO₂ + SO₂ → MnSO₄

You can also dissolve manganese alloys in sulfuric acid, however the resulting manganese sulfate will be contaminated with iron sulfate as well as other sulfates.

Projects

• Make very pure manganese dioxide (chemically or electrochemically)
• Source of manganese ions

Handling

Safety

Long-term exposure to manganese dust or compounds will lead to manganese poisoning, also known as manganism.

Storage

Manganese sulfate should be kept in closed plastic or glass bottles.

Disposal

Manganese sulfate should be precipitated to manganese dioxide and then sent to waste disposal centers. Waste batteries centers might also pick up manganese waste.

Gallery

• 

  A large crystal of MnSO₄

• 

  Ditto

• 

  Crystal compared to a coin

• 

  MnSO₄ sample and its original bottle. The sample is more pinkish in person.

References

Relevant Sciencemadness threads

• Quick Question about Manganese(II) Sulphate
• Insoluble Manganese (II) Sulfate, monohydrate