Ferric acetate is the acetate salt of the

coordination complex A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many ...

e₃O(OAc)₆(H₂O)₃sup>+ (OAc⁻ is CH₃CO₂⁻). Commonly the salt is known as "basic iron acetate". The formation of the red-brown complex was once used as a test for

ferric In chemistry, iron(III) refers to the element iron in its +3 oxidation state. In ionic compounds (salts), such an atom may occur as a separate cation (positive ion) denoted by Fe3+. The adjective ferric or the prefix ferri- is often used to s ...

ions.

Structure and synthesis

Basic iron acetate forms on treating aqueous solutions of iron(III) sources with acetate salts. A typical precursor is freshly precipitated iron oxide/hydroxide, which is halide-free. Early work showed that the cation is trinuclear. The Fe centres are equivalent, each being

octahedral In geometry, an octahedron (plural: octahedra, octahedrons) is a polyhedron with eight faces. The term is most commonly used to refer to the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at ea ...

, being bound to six oxygen ligands, including a triply bridging oxide at the center of the equilateral triangle. The compound was an early example of a molecular complex of iron that features an oxide ligand. The cation has idealized D_3h symmetry.

Reactions

The terminal aqua ligands on the trimetallic framework can be substituted with other ligands, such as

pyridine Pyridine is a basic (chemistry), basic heterocyclic compound, heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakl ...

and

dimethylformamide Dimethylformamide is an organic compound with the formula ( CH3)2NC(O)H. Commonly abbreviated as DMF (although this initialism is sometimes used for dimethylfuran, or dimethyl fumarate), this colourless liquid is miscible with water and the maj ...

. Many different salts are known by exchanging the anion, e.g. e₃(μ₃-O)(OAc)₆(H₂O)₃l. Reduction of the cation affords the neutral mixed-valence derivative that contains one ferrous and two ferric centers. Mixed metal species are known such as e₂CoO(OAc)₆(H₂O)₃

Related compounds

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

silver acetate Silver acetate is an coordination compound with the empirical formula CH3CO2Ag (or AgC2H3O2). A photosensitive, white, crystalline solid, it is a useful reagent in the laboratory as a source of silver ions lacking an oxidizing anion. Synthesis a ...

and

iron(III) chloride Iron(III) chloride is the inorganic compound with the formula . Also called ferric chloride, it is a common compound of iron in the +3 oxidation state. The anhydrous compound is a crystalline solid with a melting point of 307.6 °C. The colo ...

Uses

Materials prepared by heating iron, acetic acid, and air, loosely described as basic iron acetates, are used as

dyes A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and ...

and

mordants A mordant or dye fixative is a substance used to set (i.e. bind) dyes on fabrics by forming a coordination complex with the dye, which then attaches to the fabric (or tissue). It may be used for dyeing fabrics or for intensifying stains in ...

. Iron acetate is often brushed upon untreated wood to give it an aged appearance.

References

{{Use dmy dates, date=March 2018 Acetates Iron(III) compounds Iron complexes

Structure and synthesis

Reactions

Related compounds

Uses

See also

References