What Is Iron Nitrate?
Iron nitrate is an inorganic compound represented by the formulas Fe(NO3)3 (trivalent) and Fe(NO3)2 (divalent). The trivalent form is more stable and commonly produced compared to the divalent form.
Uses of Iron Nitrate
1. Iron Nitrate (III)
Iron nitrate (III) is utilized primarily for its solubility in alcohol, making it suitable for reactions with organic compounds. It serves as a starting material in the synthesis of metal catalysts and as a reagent in organic compound reactions, such as the nitration of benzene rings. Additionally, it is employed as a mordant in dyes, silk thickeners, tanning agents, and various analytical reagents.
2. Iron Nitrate (II)
Iron nitrate (II) hexahydrate is less stable and not commonly used, often appearing as a byproduct in the production of iron nitrate (III). Upon heating, it emits nitric oxide and precipitates hydroxide salts, enabling the production of iron nitrate (III).
Properties of Iron Nitrate
1. Iron Nitrate (III)
Iron nitrate (III) appears as a light purple solid at room temperature, with a molecular weight of 241.86 g/mol, a melting point of 47.2°C, and a specific gravity of 1.68. It decomposes at 125°C, is soluble in water and alcohols, and has a CAS number of 10421-48-4. The nonahydrate form absorbs moisture from the air, turning into a brown liquid due to its hygroscopic nature. Upon heating, it decomposes to iron oxide (Fe2O3).
2. Iron Nitrate (II)
The hexahydrate form of iron nitrate (II) is green, with a molecular weight of 287.95 g/mol, a melting point of 60.5°C, and a CAS number of 14013-86-6. It dissolves easily in water and displays acidity in aqueous solution. At temperatures below -12℃, it can precipitate as a nonahydrate.
Other Information on Iron Nitrate
1. Production Process of Iron Nitrate (III)
Iron nitrate (III) is synthesized by dissolving iron in nitric acid, resulting in either a hexahydrate or nonahydrate form depending on the concentration of the solution. The hexahydrate can be converted to the nonahydrate by treatment with fuming nitric acid or anhydrous nitric acid.
2. Production Method of Iron Nitrate (II)
Iron nitrate (II) is produced through the double decomposition of iron nitrate (II) with nitric acid or barium nitrate, or by reducing iron nitrate (III) with silver, typically resulting in a light green hexahydrate that turns dark red under dry conditions.
3. Hazards of Iron Nitrate
Both divalent and trivalent forms of iron nitrate are oxidizing and can cause irritation; hence, protective gear such as rubber gloves, safety glasses, and a lab coat are recommended during handling. Iron nitrate (II) is especially sensitive to air and should be kept in a saturated solution to avoid decomposition.