Iron(III) nitrate
Chemical structure of ferric nitrate aquo complex
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Sample of ferric nitrate nonahydrate
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| Names | |
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| IUPAC name
Iron(III) nitrate
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| Other names
Ferric nitrate
Nitric acid, iron(3+) salt | |
| Identifiers | |
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3D model (JSmol)
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PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| Fe(NO3)3 | |
| Molar mass | 403.999 g/mol (nonahydrate) 241.86 g/mol (anhydrous) |
| Appearance | Pale violet crystals hygroscopic |
| Density | 1.68 g/cm3 (hexahydrate) 1.6429 g/cm3(nonahydrate) |
| Melting point | 47.2 °C (117.0 °F; 320.3 K) (nonahydrate) |
| Boiling point | 125 °C (257 °F; 398 K) (nonahydrate) |
| 150 g/100 mL (hexahydrate) | |
| Solubility | soluble in alcohol, acetone |
| +15,200.0·10−6 cm3/mol | |
| Structure | |
| octahedral | |
| Hazards[2] | |
| GHS labelling: | |
| Ox. sol. 3Acute tox. 4 (oral); Eye irrit. 1 | |
| Warning | |
| H272, H302, H319 | |
| P210, P220, P221, P264, P270, P280, P301+P312, P305+P351+P338, P330, P337+P313, P370+P378, P501 | |
| NFPA 704 (fire diamond) | |
| Flash point | non-flammable |
| NIOSH (US health exposure limits): | |
REL (Recommended)
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TWA 1 mg/m3[1] |
| Related compounds | |
Other anions
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Iron(III) chloride Iron(III) sulfate |
Related compounds
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Iron(II) 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(III) nitrate, or ferric nitrate, is the name used for a series of inorganic compounds with the formula Fe(NO3)3.(H2O)n. Most common is the nonahydrate Fe(NO3)3.(H2O)9. The hydrates are all pale colored, water-soluble paramagnetic salts.
Hydrates
[edit | edit source]Iron(III) nitrate is deliquescent, and it is commonly found as the nonahydrate Fe(NO3)3·9H2O, which forms colourless to pale violet crystals. This compound is the trinitrate salt of the aquo complex [Fe(H2O)6]3+.[3]
Other hydrates Fe(NO
3)
3·xH
2O, include:
- tetrahydrate (x=4), more precisely triaqua dinitratoiron(III) nitrate monohydrate, [Fe(NO3)2(H2O)3]NO3·H2O, has complex cations wherein Fe3+ is coordinated with two nitrate anions as bidentate ligands and three of the four water molecules, in a pentagonal bipyramid configuration with two water molecules at the poles.[4]
- pentahydrate (x=5), more precisely penta-aqua nitratoiron(III) dinitrate, [Fe(NO3)(H2O)5](NO3)2, in which the Fe3+ ion is coordinated to five water molecules and a unidentate nitrate anion ligand in octahedral configuration.[4]
- hexahydrate (x=6), more precisely hexaaquairon(III) trinitrate, [Fe(H2O)6](NO3)3, where the Fe3+ ion is coordinated to six water molecules in octahedral configuration.[4]
Reactions
[edit | edit source]Iron(III) nitrate is a useful precursor to other iron compounds because the nitrate is easily removed or decomposed. It is for example, a standard precursor to potassium ferrate K2FeO4.[5]
When dissolved, iron(III) nitrate forms yellow solutions. When this solution is heated to near boiling, nitric acid evaporates and a solid precipitate of iron(III) oxide Fe
2O
3 appears.[6] Another method for producing iron oxides from this nitrate salt involves neutralizing its aqueous solutions.[7]
Preparation
[edit | edit source]The compound can be prepared by treating iron metal powder with nitric acid, as summarized by the following idealized equation:[8]
- Fe + 4 HNO3 + 7 H2O → Fe(NO3)3(H2O)9 + NO
Applications
[edit | edit source]Ferric nitrate has no large scale applications. It is a catalyst for the synthesis of sodium amide from a solution of sodium in ammonia:[9]
- 2 NH3 + 2Na → 2 NaNH2 + H2
Certain clays impregnated with ferric nitrate have been shown to be useful oxidants in organic synthesis. For example, ferric nitrate on Montmorillonite—a reagent called Clayfen—has been employed for the oxidation of alcohols to aldehydes and thiols to disulfides.[10]
Ferric nitrate solutions are used by jewelers and metalsmiths to etch silver and silver alloys.
References
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- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c H. Schmidt, A. Asztalos, F. Bok and W. Voigt (2012): "New Iron(III) Nitrate Hydrates: Fe(NO3|3·xH2O with x = 4, 5 and 6". Acta Crystallographica Section C - Inorganic Compounds, volume C68, pages i29-i33. Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Egon Matijević and Paul Scheiner (1978): "Ferric Hydrous Oxide Sols: III. Preparation of Uniform Particles by Hydrolysis of Fe(III)-Chloride, -Nitrate, and -Perchlorate solutions". Journal of Colloid and Interface Science, volume 63, issue 3, pages 509-524. Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).; Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).. As of 2007, 22 other entries describe similar preparations in Organic Syntheses
- ^ Cornélis, A. Laszlo, P.; Zettler, M. W. "Iron(III) Nitrate–K10 Montmorillonite Clay" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)..