Potassium ferrate
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| Potassium ferrate | |
|---|---|
| Image:Potassium ferrate.jpg | |
| General | |
| Systematic name | Potassium ferrate(VI) |
| Other names | Potassium ferrate |
| Molecular formula | K2FeO4 |
| SMILES | ? |
| Molar mass | 198.0392 g/mol |
| Appearance | Dark, nearly black solid |
| CAS number | [39469-86-8] |
| Properties | |
| Density and phase | ? g/cm³, ? |
| Solubility in water | soluble |
| Melting point | >198 °C (decomposition temp) |
| Basicity (pKb) | ? |
| Structure | |
| Coordination geometry |
Tetrahedral oxyanion |
| Crystal structure | K2SO4 motif |
| Dipole moment | 0 D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | oxidizing |
| NFPA 704 | |
| Flash point | non-combustible |
| R/S statement | R: ? S: ? |
| RTECS number | ? |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other anions | KMnO4 K2MnO4 K2CrO4 K2RuO4 |
| Other cations | BaFeO4 Na2FeO4 |
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references |
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Potassium ferrate is the chemical compound with the formula K2FeO4. This purple, paramagnetic salt consists of isolated K+ and the FeO42- anion. It is a rare example of an Fe(VI) compound.
As a dry solid, K2FeO4 is stable but it oxidizes water, forming oxygen and iron oxy hydroxides. At high pH, aqueous solutions are, however, stable, being deep purple similar in appearance to potassium permanganate. K2FeO4 is a stronger oxidizing agent than KMnO4.
Contents |
[edit] Applications of its redox properties
Because the side products of its redox reactions are benign rust-like iron oxides, K2FeO4 is considered by some to be a "green oxidant." Indeed it has been employed for waste-water treatment as an oxidant for organic contaminants and as a biocide. The reduced iron(III) oxyhydroxide is an excellent flocculant. K2FeO4 oxidizes primary alcohols. It has also attracted attention as a potential cathode material for batteries.
[edit] Synthesis
Georg Ernst Stahl (1660 – 1734) first discovered that the residue formed by igniting a mixture of potassium nitrate (saltpetre) and iron powder dissolved in water to give a purple solution. Edmond Fremy (1814 – 1894) later discovered that fused potassium hydroxide reacted with iron(III) oxide chemically, and the compound produced was soluble in water and corresponds to the composition of potassium manganate. K2FeO4 is conveniently prepared by oxidizing an alkaline solution of an iron(III) salt with concentrated chlorine bleach.[1]
[edit] Safety
K2FeO42- is a potent oxidizer.
[edit] See also
[edit] References
- ^ Schreyer, J. M.; Thompson, G. W.; Ockerman, L. T. "Potassium Ferrate(VI)" Inorganic Syntheses, 1953 volume IV, pages 164-168.
