Iron(III) nitrate

Summary

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.

Iron(III) nitrate
(Fe(aq)6)(NO3)3.svg
Iron(III) nitrate nonahydrate
Names
IUPAC name
Iron(III) nitrate
Other names
Ferric nitrate
Nitric acid, iron(3+) salt
Identifiers
  • [https://commonchemistry.cas.org/detail?cas_rn=10421-48-4 10421-48-4 10421-48-4] checkY
  • [https://commonchemistry.cas.org/detail?cas_rn=7782-61-8 7782-61-8 7782-61-8] (nonahydrate) checkY
3D model (JSmol)
  • Interactive image
ChemSpider
  • 10670706 checkY
ECHA InfoCard 100.030.805 Edit this at Wikidata
  • 25251
RTECS number
  • NO7175000
UNII
  • N8H8402XOB checkY
  • InChI=1S/Fe.3NO3.9H2O/c;3*2-1(3)4;;;;;;;;;/h;;;;9*1H2/q+3;3*-1;;;;;;;;; checkY
    Key: SZQUEWJRBJDHSM-UHFFFAOYSA-N checkY
  • InChI=1/Fe.3NO3.9H2O/c;3*2-1(3)4;;;;;;;;;/h;;;;9*1H2/q+3;3*-1;;;;;;;;;
    Key: SZQUEWJRBJDHSM-UHFFFAOYAC
  • [Fe+3].O.O.O.O.O.O.O.O.O.O=[N+]([O-])[O-].[O-][N+]([O-])=O.[O-][N+]([O-])=O
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[3]
GHS labelling:
Ox. sol. 3Acute tox. 4 (oral); Eye irrit. 1[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)
TWA 1 mg/m3[2]
Safety data sheet (SDS) External SDS
Related compounds
Other anions
Iron(III) chloride
Iron(III) sulfate
Related compounds
Iron(II) nitrate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Infobox references

HydratesEdit

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+.[4] Other hydrates Fe(NO
3
)
3
·xH
2
O
, include:

  • tetrahydrate (x=4), more precisely triaqua dinitratoiron(III) nitrate monohydrate, [Fe(NO
    3
    )
    2
    (H
    2
    O)+
    3
    ]
    [NO
    3
    ]
    ·H
    2
    O
    , has complex cations where Fe3+
    atom 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.[5]
  • pentahydrate (x=5), more precisely penta-aqua nitratoiron(III) dinitrate, [Fe(NO
    3
    )(H
    2
    O)2+
    5
    ]
    [NO
    3
    ]
    2
    , in which the Fe3+
    atom is coordinated to five water molecules and a unidentate nitrate anion ligand in octahedral configuration.[5]
  • hexahydrate (x=6), more precisely hexaaquairon(III) trinitrate, [Fe(H
    2
    O)3+
    6
    ]
    [NO
    3
    ]
    3
    , where the Fe3+
    atom is coordinated to six water molecules in octahedral configuration.[5]

Chemical propertiesEdit

DecompositionEdit

When dissolved, iron(III) nitrate forms yellow solution due to hydrolysis. When heated to near boiling, nitric acid will evaporate from the solution, and all the iron will precipitate as iron(III) oxide Fe
2
O
3
.[6]

The compound will dissolve in molten stearic acid and decompose at about 120 °C to give iron(III) oxide-hydroxide FeO(OH).[7]

PreparationEdit

The compound can be prepared by treating iron metal powder with nitric acid.

Fe + 4 HNO3 → Fe(NO3)3 + NO + 2 H2O.

ApplicationsEdit

Ferric nitrate has no large scale applications. It is a catalyst for the synthesis of sodium amide from a solution of sodium in ammonia:[8]

2 NH3 + 2 Na → 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.[9]

Ferric nitrate solutions are used by jewelers and metalsmiths to etch silver and silver alloys.

ReferencesEdit

  1. ^ "Iron(III) Nitrate Nonahydrate". American Elements. Retrieved June 20, 2019.
  2. ^ NIOSH Pocket Guide to Chemical Hazards. "#0346". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ HSNO Chemical Classification Information Database, New Zealand Environmental Risk Management Authority, retrieved 2010-09-19.
  4. ^ Hair, Neil J.; Beattie, James K. (1977). "Structure of Hexaaquairon(III) Nitrate Trihydrate. Comparison of Iron(II) and Iron(III) Bond Lengths in High-Spin Octahedral Environments". Inorganic Chemistry. 16 (2): 245–250. doi:10.1021/ic50168a006.
  5. ^ a b c H. Schmidt, A. Asztalos, F. Bok and W. Voigt (2012): "New iron(III) nitrate hydrates: Fe(NO
    3
    )
    3
    ·xH
    2
    O
    with x = 4, 5 and 6". Acta Crystallographica Section C - Inorganic Compounds, volume C68, pages i29-i33. doi:10.1107/S0108270112015855
  6. ^ 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. doi:10.1016/S0021-9797(78)80011-3
  7. ^ Dan Li, Xiaohui Wang, Gang Xiong, Lude Lu, Xujie Yang and Xin Wang (1997): "A novel technique to prepare ultrafine Fe
    2
    O
    3
    via hydrated iron(III) nitrate". Journal of Materials Science Letters volume 16, pages 493–495 doi:10.1023/A:1018528713566
  8. ^ Hampton, K. G.; Harris, T. M.; Hauser, C. R. (1973). "2,4-Nonanedione". Organic Syntheses.; Collective Volume, vol. 5, p. 848 As of 2007, 22 other entries describe similar preparations in Organic Syntheses
  9. ^ 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. doi:10.1002/047084289X.