Iron compounds

• Iron oxides (FeO, Fe₃O₄, and Fe₂O₃) are ores used for iron production (see bloomery and blast furnace). They are also used as a catalyst in the Space Shuttle Solid Rocket Boosters,^[16] and in the production of magnetic storage media in computers. They are often mixed with other compounds, and retain their magnetic properties in solution.
• Iron(II) acetate (Fe(CH₃CO₂)₂ (ferrous acetate) is used as a mordant in the dyeing of cloth and leather, and as a wood preservative.
• Iron(III) ammonium citrate (C₆H_5+4yFe_xN_yO₇) is used in blueprints.
• Iron(III) arsenate (FeAsO₄) is used in insecticides.
• Iron(III) chloride (FeCl₃) is used in water purification and sewage treatment, in the dyeing of cloth, as a colouring agent in paints, as an additive in animal feed, and as an etchant for copper in the manufacture of printed circuit boards.
• Iron(III) chromate (Fe₂(CrO₄)₃) is a yellow pigment for paints and ceramics.
• Iron(III) hydroxide (Fe(OH)₃) is used as a brown pigment for rubber and in water purification systems.
• Iron(III) phosphate (FePO₄) is used in fertilizers and as an additive in human and animal food.
• Iron(II) gluconate (Fe(C₆H₁₁O₇)₂) is used as a dietary supplement in iron pills.
• Iron(II) oxalate (FeC₂O₄) is used as yellow pigment for paints, plastics, glass and ceramics, and in photography.
• Iron(II) sulfate (FeSO₄) is used in water purification and sewage treatment systems, as a catalyst in the production of ammonia, as an ingredient in fertilizer, herbicide, and moss killer, as an additive in animal feed, in wood preservative, and as an additive to flour to increase nutritional iron levels. Experimental iron fertilization of areas of the ocean using iron(II) sulfate has proven successful in increasing plankton growth.^[17][18][19]

Iron chloride hexahydrate

Iron-based coordination complexes are being increasingly studied for Fisher-Tropsch and transfer-hydrogenation catalysis due to relatively high abundance and low cost of the metal. Specifically, iron analogues of existing ruthenium and osmium-based catalysts are being tested for activity because iron is isoelectronic with the more expensive second- and third-row transition metals and therefore exhibits similar reactivity.^[20] The use of iron compounds in organic synthesis is mainly for the reduction of nitro compounds.^[21] Additionally, iron has been used for desulfurizations,^[22] reduction of aldehydes,^[23] and the deoxygenation of amine oxides