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3D model (
JSmol)
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PubChem
CID
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UNII |
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CompTox Dashboard (
EPA)
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Properties | |
Fe(NO3)2 | |
Molar mass | 179.86 g/mol |
Appearance | Green crystals (hexahydrate) |
Melting point | 60 °C (140 °F; 333 K) [2] (hexahydrate) |
Boiling point | 61 °C (142 °F; 334 K) [1] (decomposes) |
87.525 g/100 mL | |
Structure | |
Orthorhombic [3] | |
Thermochemistry | |
Std enthalpy of
formation (ΔfH⦵298) |
-497.9 kJ/mol [1] |
Hazards | |
Lethal dose or concentration (LD, LC): | |
LD50 (
median dose)
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428 mg/kg (subcutaneous, rabbit) [4] |
Related compounds | |
Other
anions
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Iron(II) phosphate |
Other
cations
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Manganese(II) nitrate Cobalt(II) nitrate |
Related compounds
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Iron(III) nitrate |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
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Iron(II) nitrate is the nitrate salt of iron(II). It is commonly encountered as the green hexahydrate, Fe(NO3)2·6H2O, which is a metal aquo complex, however it is not commercially available unlike iron(III) nitrate due to its instability to air. The salt is soluble in water serves as a ready source of ferrous ions.
No structure of any salt Fe(NO3)2·xH2O has been determined by X-ray crystallography. Nonetheless, the nature of the aquo complex [Fe(H2O)62+ is well known and relatively insensitive to the anion. The Fe-O distances are longer for [Fe(H2O)62+ (2.13 Å) than for the ferric analogue [Fe(H2O)63+ (1.99 Å). [5] Both [Fe(H2O)6n+ complexes are high spin, which results in pale colors, paramagnetism, and weak Fe-O bonds.
Iron(II) nitrate can be produced in multiple ways, such as the reaction of iron metal with cold dilute nitric acid:
If this reaction is conducted below -10 °C, nonahydrate is produced. It readily releases water to give the hexahydrate. [1]
The above reaction can also co-produce ferric nitrate. Reacting iron(II) sulfate and lead nitrate under dilute ethanol and then evaporating the solution leads to the formation of the green crystals of the hexahydrate. A solution of iron(II) nitrate is produced by the ion-exchange reaction of iron(II) sulfate and barium nitrate, producing a concentration of up to 1.5 M due to the limited solubility of barium nitrate. [1] [6] [7]
The solution of the iron(II) nitrate- hydrazine complex is produced by the reaction of hydrazine nitrate and ferric nitrate at 40 °C with copper(II) nitrate as a catalyst: [8]
If the compound is used in situ, the compound is produced by the reaction of iron(II) chloride and calcium nitrate: [9] [10]
The hexahydrate melts at 60 °C and then decomposes at 61 °C into iron(III) oxide rather than iron(II) oxide. [1] A solution of iron(II) nitrate is much more stable, decomposing at 107 °C to iron(III), with the presence of nitric acid lowering the decomposition temperature. Concentrated nitric acid oxidizes iron(II) nitrate into iron(III) nitrate: [6]
Iron(II) nitrate has no uses, however, there is a potential use for dye removal. [10] [9]