Iron(III) sulfate

From Sciencemadness Wiki
Jump to: navigation, search
Iron(III) sulfate
IUPAC name
Iron(III) sulfate
Other names
Ferric sulfate
Sulfuric acid, iron(3+) salt (3:2)
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
Slightly soluble
Solubility Sparingly soluble in alcohol
Negligible in acetone, ethyl acetate
Insoluble in sulfuric acid, ammonia
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.



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

Addition of a base, like sodium hydroxide to an aqueous solution of ferric sulfate will precipitate iron(III) hydroxide.


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.


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

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


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).




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


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


Ferric sulfate can be neutralized with slaked lime.


Relevant Sciencemadness threads