Ferrous sulfate << FEHR uhs SUHL fayt >> is a substance which occurs in light-green crystals. The crystals turn rusty brown when they react with oxygen in moist air. Ferrous sulfate is an iron salt of sulfuric acid. It can be made by combining iron with sulfuric acid or by oxidizing iron pyrites, a compound of iron and sulfur. Ferrous sulfate is used to dye fabrics and leather and to make ink. It is also used to purify water, and as a disinfectant, wood preservative, and weedkiller.
