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. ...

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 sp ...

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 a ...

, 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 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, weakly alkaline, water-miscible liquid with a ...

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.

Uses

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