Together with other iron compounds, ferrous sulfate is used to fortify foods and to treat and prevent iron deficiency anemia. Constipation is a frequent and uncomfortable side effect associated with the administration of oral iron supplements. Stool softeners often are prescribed to prevent constipation.
Ferrous sulfate was used in the manufacture of inks, most notably iron gall ink.
Sometimes, it is included in canned black olives as an artificial colorant.
Ferrous sulfate can also be used to stain concrete and some limestones and sandstones a yellowish rust color.
Woodworkers use ferrous sulfate solutions to color maple wood a silvery hue.
Iron (II) sulfate is sold as ferrous sulfate, a soil amendment for lowering the pH of a high alkaline soil so that plants can access the soil's nutrients.
In horticulture it is used for treating iron chlorosis. Although not as rapid-acting as ferric edta, its effects are longer-lasting. It can be mixed with compost and dug into the soil to create a store which can last for years. It is also used as a lawn conditioner, and moss killer.
In the second half of the 1850s ferrous sulfate was used as a photographic developer for collodion process images.
Ferrous sulfate is sometimes added to the cooling water flowing through the brass tubes of turbine condensers to form a corrosion-resistant protective coating.
It is used in gold refining to precipitate metallic gold from auric chloride solutions (gold dissolved in solution with aqua regia).
It has been used in the purification of water by flocculation and for phosphate removal in municipal and industrial sewage treatment plants to prevent eutrophication of surface water bodies.
It is used as a traditional method of treating wood panelling on houses, either alone, dissolved in water, or as a component of water-based paint.
Green vitriol is also a useful reagent in the identification of mushrooms.
|Molar mass||151.91 g/mol (anhydrous)
169.93 g/mol (monohydrate)
241.99 g/mol (pentahydrate)
260.00 g/mol (hexahydrate)
278.02 g/mol (heptahydrate)
|Appearance||White crystals (anhydrous)
White-yellow crystals (monohydrate)
Blue-green crystals (heptahydrate)
|Density||3.65 g/cm3 (anhydrous)
3 g/cm3 (monohydrate)
2.15 g/cm3 (pentahydrate)
1.934 g/cm3 (hexahydrate)
1.895 g/cm3 (heptahydrate)
|Melting point||680 °C (1,256 °F; 953 K)
300 °C (572 °F; 573 K)
60–64 °C (140–147 °F; 333–337 K)
|Solubility in water||Monohydrate:
44.69 g/100 mL (77 °C)
35.97 g/100 mL (90.1 °C)
15.65 g/100 mL (0 °C)
20.5 g/100 mL (10 °C)
29.51 g/100 mL (25 °C)
39.89 g/100 mL (40.1 °C)
51.35 g/100 mL (54 °C)
|Solubility||Negligible in alcohol|