Ferric acetate is the iron compound with the formula . This red brown solid is the acetate salt of the
coordination complex
A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...
e3O(OAc)6(H2O)3sup>+ (OAc
− is CH
3CO
2−). 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) or ''ferric'' refers to the chemical element, element iron in its +3 oxidation number, oxidation state. ''Ferric chloride'' is an alternative name for iron(III) chloride (). The adjective ''ferrous'' is used instead for i ...
ions.
Structure and synthesis
left, 200px, structure of the cation called basic iron acetate as determined from X-ray crystallography
Basic iron acetate forms on treating aqueous solutions of iron(III) sources with acetate salts. It is slowly soluble in water and poorly soluble in acetic acid.
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 (: octahedra or octahedrons) is any polyhedron with eight faces. One special case is the regular octahedron, a Platonic solid composed of eight equilateral triangles, four of which meet at each vertex. Many types of i ...
, 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
Symmetry () in everyday life refers to a sense of harmonious and beautiful proportion and balance. In mathematics, the term has a more precise definition and is usually used to refer to an object that is Invariant (mathematics), invariant und ...
.
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, weak ...
and
dimethylformamide
Dimethylformamide, DMF is an organic compound with the chemical formula . Its structure is . Commonly abbreviated as DMF (although this initialism is sometimes used for 2,5-dimethylfuran, dimethylfuran, or dimethyl fumarate), this colourless liqui ...
. 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), manganese(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 a 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 an ...
and iron(III) chloride
Iron(III) chloride describes the inorganic compounds with the formula (H2O)x. Also called ferric chloride, these compounds are some of the most important and commonplace compounds of iron. They are available both in anhydrous and in hydrated f ...
.
Uses
Materials prepared by heating iron, acetic acid, and air, loosely described as basic iron acetates, are used as dyes
Juan de Guillebon, better known by his stage name DyE, is a French musician. He is known for the music video of the single "Fantasy (DyE song), Fantasy" from his first album ''Taki 183 (album), Taki 183''. This video became popular, attracting ...
and mordants
A mordant or dye fixative is a substance used to set (i.e., bind) dyes on fabrics. It does this 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 ...
.[
Iron acetate is often brushed upon untreated wood to give it an aged appearance.
]
See also
* Iron(II) acetate
* Cobalt(II) acetate
* Rhodium(II) acetate
* Manganese(III) acetate
* Chromium(III) acetate
References
{{Use dmy dates, date=March 2018
Acetates
Iron(III) compounds
Iron complexes