Ferric acetate is the acetate salt of the
coordination complex 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 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, 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 (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definit ...
.
Reactions
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.
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 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 col ...
.
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.[
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
Rhodium(II) acetate is the coordination compound with the formula Rh2(AcO)4, where AcO− is the acetate ion (). This dark green powder is slightly soluble in polar solvents, including water. It is used as a catalyst for cyclopropanation of a ...
*Manganese(III) acetate
Manganese(III) acetate describes a family of materials with the approximate formula Mn(O2CCH3)3. These materials are brown solids that are soluble in acetic acid and water. They are used in organic synthesis as oxidizing agents.
Structure
Altho ...
* Chromium(III) acetate
References
{{Use dmy dates, date=March 2018
Acetates
Iron(III) compounds
Iron complexes