IRON(II) SULFATE

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Iron(II) sulfate
Systematic name	Iron(II) sulfate
Other names	ferrous sulfate green vitriol iron vitriol copperas melanterite szomolnokite
Molecular formula	FeSO4·H2O FeSO4·4H2O FeSO4·5H2O FeSO4·7H2O
Molar mass	151.908 g/mol (anhydrous) 169.923 g/mol (monohydrate) 224.120 g/mol (tetrahydrate) 242.135 g/mol (pentahydrate) 278.05 g/mol (heptahydrate)
CAS number	[7720-78-7] (heptahydrate)
Appearance	blue/green or white crystals
Crystal structure	monoclinic
Density	1.898 g/cm3
Solubility (water)	Soluble
Melting point	64°C
Boiling point	90°C ''(becomes FeSO4·H2O)''

'Iron(II) sulfate' is the chemical compound with the formula (FeSO₄). Also known as 'ferrous sulfate', 'ferrous sulphate', or 'copperas', iron(II) sulfate is most commonly encountered as the blue-green heptahydrate.

Contents

Hydrates

Production

Uses

Nutrition

Colouring

Other uses

See also

References

External links

Hydrates

Iron(II) sulphate can be found in various states of hydration, and several of these forms exist in nature.

★ FeSO₄·H₂O (mineral: szomolnokite)

★ FeSO₄·4H₂O

★ FeSO₄·5H₂O (mineral: siderotil)

★ FeSO₄·7H₂O (mineral: melanterite)
At 90°C, the heptahydrate loses water to form the colourless monohydrate, also called green vitriol or copperas.

Production

In the finishing of steel prior to plating or coating, the steel sheet or rod is passed through pickling baths of sulfuric acid. This treatment produces large quantities of iron(II) sulfate as a waste product. Iron(II) sulfate is prepared commercially by oxidation of pyrite, or by treating iron with sulfuric acid.

Uses

Nutrition

Ferrous sulfate is used to treat iron-deficiency anemia. Side effects of therapy may include nausea and epigastric abdominal discomfort after taking iron. These side effects may be minimized by taking ferrous sulfate at bedtime.
Ferrous sulfate is also also used to fortify various foods with iron, for example, the enriched corn meal in Cheetos^[1].

Colouring

Ferrous sulfate is used in the manufacture of inks, most notably iron gall ink, which was used from the middle ages until the American Revolution. It also finds use in wool dyeing as a mordant, and in water purification as a substitute for aluminium sulfate.
Two different methods for the direct application of indigo dye were developed in England in the eighteenth century and remained in use well into the nineteenth century. One of these, known as ''china blue'', involved iron(II) sulfate. After printing an insoluble form of indigo onto the fabric, the indigo was reduced to ''leuco''-indigo in a sequence of baths of ferrous sulfate (with reoxidation to indigo in air between immersions). The china blue process could make sharp designs, but it could not produce the dark hues of other methods.
Ferrous sulfate can also be used to stain concrete a yellowish rust color.^[2]
Woodworkers use ferrous sulfate solutions to color maple wood a silvery hue.

Other uses

In horticulture it is used as a lawn conditioner and moss killer.
In the second half of the 19th century, Ferrous Sulfate was also used as a photographic developer for Collodion process images.
Ferrous sulphate is sometimes added to the cooling water flowing through the brass tubes of a turbine condenser. It forms an erosion-resistant, protective coating on the inside of the tube.

See also

★ Iron(III) sulfate, the other common simple sulfate of iron.

★ Ammonium iron(II) sulfate, a common double salt of ammonium sulfate with iron(II) sulfate.

References

1. Product Information - Smart Spot
2. How To Stain Concrete with Iron Sulfate

External links

★ Product Information