Iron(III) sulfate

Iron(III) sulfate

Names
IUPAC name Iron(III) sulfate
Other names Ferric sulfate Sulfuric acid, iron(3+) salt (3:2)
Properties
Chemical formula	Fe2(SO4)3
Molar mass	399.88 g/mol (anhydrous) 489.96 g/mol (pentahydrate) 562.00 g/mol (nonahydrate)
Appearance	Gray-white solid
Odor	Odorless
Density	3.097 g/cm3 (anhydrous) 1.898 g/cm3 (pentahydrate)
Melting point	480 °C (896 °F; 753 K) (anhydrous) 175 °C (347 °F) (nonahydrate)
Boiling point	Decomposes
Solubility in water	Slightly soluble
Solubility	Sparingly soluble in alcohol Negligible in acetone, ethyl acetate Insoluble in sulfuric acid, ammonia
Hazards
Safety data sheet	Sigma-Aldrich (hydrated)
Flash point	Non-flammable
Related compounds
Related compounds	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

Iron(III) sulfate also known as ferric sulfate or vitriol of Mars/vitriol martial, is the chemical compound with the formula Fe₂(SO₄)₃, an iron salt.

Properties

Chemical

Ferric sulfate is used in industry as a coagulant for waste.

Physical

Ferric sulfate is a yellow, hygroscopic compound. It is soluble in water, poorly soluble in organic solvents such as acetone, ethanol or various acetates. It is insoluble in sulfuric acid. The anhydrous form melts at 480 °C.

Availability

Iron(III) sulfate is available from many chemical suppliers.

One such seller on Amazon sells 4.5 kg of ferric sulfate at 18.40 $.

Preparation

Iron(III) sulfate can be made by reacting sulfuric acid, with a hot solution of ferrous sulfate, and an oxidizing agent, such as hydrogen peroxide.

2 FeSO₄ + H₂SO₄ + H₂O₂ → Fe₂(SO₄)₃ + 2H₂O

This method is similar to the one used for obtaining ferric chloride.

n.b. Hydrogen peroxide is also a reducing agent and will reduce Iron(III) to to Iron(II).

Projects

• Make Fenton's reagent
• Coagulant for waste water

Handling

Safety

Ferric sulfate both solid and as solution is corrosive to tissue and metallic objects.

Storage

Ferric sulfate should be stored in a tightly closed container, in a cool, dry place.

Disposal

Ferric sulfate can be neutralized with slaked lime.

References

Relevant Sciencemadness threads

• Iron (III) Sulfate (ferric sulfate) synthesis