Examples of Iron Compounds
Here is more information about iron(II) sulfate: Iron(II) sulfate also known as ferrous sulfate has the formula FeSO4. It is probably the longest-known iron(II) compound which was famous as green vitriol in the past times. Crystals of FeSO4 (ferrous sulfate), FeSO4.H2O (ferrous sulfate monohydrate) and FeSO4.7H2O (ferrous sulfate heptahydrate) are respectively white, yellowish-white and bluish-green. Main industrial production method of iron(II) sulfate is pickling process of steel in which the surface of steel is treated with dilute sulfuric acid to eliminate metal impurities where reaction of dilute sulfuric acid with iron is unavoidable and ferrous sulfate is produced as a by-product of the steel industry. Reaction of iron with dilute sulfuric acid is also used in the laboratory to produce ferrous sulfate heptahydrate. Instead of iron metal, ferrous oxide (FeO) or ferrous carbonate (FeCO3) may be used to react with dilute sulfuric acid and produce ferrous sulfate where in any case, reaction should be followed by rapid crystallization to avoid oxidization of Fe2+ to Fe3+ by oxygen of air (or it should be done under a non-oxidizing atmosphere). Iron(II) sulfate has many applications like use in dyeing, writing ink, electroplating baths, weed-killer, water purification and production of Prussian blue (a famous dark blue pigment).