Iron(III) acetate

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Iron(III) acetate[1]
BasicFeacetate.png
Basic-iron-acetate-cation-from-xtal-2008-CM-3D-ellipsoids.png
Names
IUPAC name
iron(III) acetate
Other names
basic iron(III) acetate , iron(III) oxyacetate, iron(III) Acetate
Identifiers
3D model (Jmol)
ChemSpider
ECHA InfoCard 100.030.838
UNII
Properties
C14H27Fe3O18
Molar mass 650.9 g/mol
Appearance brownish-red amorphous powder
Solubility soluble in ethanol[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Ferric acetate is the coordination compound more commonly known as "basic iron acetate". With the formula [Fe3O(OAc)6(H2O)3]OAc (OAc is CH3CO2), it is a salt, composed of the cation [Fe3(μ3-O)(OAc)6(H2O)3]+ and an acetate anion.[3] The formation of the red-brown complex has long been used as a test for ferric ions.[4]

Structure and synthesis[edit]

Basic iron acetate forms on treating aqueous solutions of iron(III) sources with acetate salts.[5] Solid iron may be mixed with hydrogen peroxide to form iron(II and/or III) hydroxide, which can then react with vinegar/acetic acid or acetate salts to form iron(III) acetate.

Early work showed that it is trinuclear.[6] The Fe centres are equivalent, each being octahedral, being bound to six oxygen ligands, including a triply bridging oxide at the center of the equilateral triangle.[7] The compound was an early example of a molecular compound of iron that features an oxide ligand. Ignoring its 24 hydrogen centres, the cation has D3h symmetry.

Reactions[edit]

The terminal aqua ligands on the trimetallic framework can be substituted with other ligands, such as pyridine and dimethylformamide. Many different salts are known by exchanging the anion, e.g. [Fe33-O)(OAc)6(H2O)3]Cl. Reduction of the cation affords the neutral mixed-valence derivative that contains one ferrous and two ferric centers.[3] Mixed metal species are known such as [Fe2CoO(OAc)6(H2O)3].[8]

Related compounds[edit]

Chromium(III), ruthenium(III), vanadium(III), and rhodium(III) form analogous compounds.[9] Iron(III) acetate (lacking the oxo ligand) has been claimed as a red coloured compound from the reaction of silver acetate and iron(III) chloride.[10]

Uses[edit]

Materials prepared by heating iron, acetic acid, and air, loosely described as basic iron acetates, are used as dyes and mordants.[3]

References[edit]

  1. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. pp. 4–63. ISBN 0-8493-0487-3. 
  2. ^ "Iron(III) Acetate". EndMemo. Retrieved 2015-04-18. 
  3. ^ a b c J., Burgess; M. V., Twigg (2005). R. Bruce, King; J., Wiley, eds. Encyclopedia of inorganic chemistry (2nd ed.). New York: Wiley. ISBN 978-0-470-86078-6. 
  4. ^ H., Brearley; F., Ibbotson (1902). The Analysis of Steel-Works Materials. London ; New York: Longmans, Green. 
  5. ^ W., Simon. Manual of Chemistry. p. 474. ISBN 1406733350. 
  6. ^ Weinland, R.; Dinkelacker, P. (July 1909). "Über Salze einer Hexaacetato(formiato)-trichrombase. II". Berichte der deutschen chemischen Gesellschaft. 42 (3): 2997–3018. doi:10.1002/cber.19090420318. 
  7. ^ Figgis, B. N.; Robertson, G. B. (13 February 1965). "Crystal-Molecular Structure and Magnetic Properties of Cr3(CH3.COO)6OCl.5H2O". Nature. 205 (4972): 694–695. doi:10.1038/205694a0.  This paper describes the isostructure chromium and iron compounds.
  8. ^ Blake, Antony B.; Yavari, Ahmad; Hatfield, William E.; Sethulekshmi, C. N. (1985). "Magnetic and spectroscopic properties of some heterotrinuclear basic acetates of chromium(III), iron(III), and divalent metal ions". Journal of the Chemical Society, Dalton Transactions (12): 2509. doi:10.1039/DT9850002509. 
  9. ^ Holleman, A. F.; Wiberg, E. (2001), Inorganic Chemistry, San Diego: Academic Press, ISBN 0-12-352651-5 
  10. ^ Paul, Ram C.; Narula, Ramesh C.; Vasisht, Sham K. (December 1978). "Iron(III) acetates". Transition Metal Chemistry. 3 (1): 35–38. doi:10.1007/BF01393501.