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Potassium ferrate is the chemical compound with the formula K2FeO4. This purple salt is paramagnetic, and is a rare example of an iron(VI) compound. In most of its compounds, iron has the oxidation state +2 or +3 (Fe2+ or Fe3+). Reflecting its high oxidation state, FeO42− is a powerful oxidizing agent. K2FeO4 has attracted interest for applications in "green chemistry" because the by-products of its use, iron oxides, are environmentally innocuous. In contrast, some related oxidants such as chromate are considered environmentally hazardous. However, the main difficulty with the use of K2FeO4 is that it is often too reactive, as indicated by the fact that it decomposes in contact with water.〔Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.〕 : 4 K2FeO4 + 4 H2O → 3 O2 + 2 Fe2O3 + 8 KOH ==Synthesis and structure== 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 Frémy (1814 – 1894) later discovered that fusion of potassium hydroxide and iron(III) oxide in air produced a compound that was soluble in water. The composition corresponded to that of potassium manganate. In the laboratory, K2FeO4 is prepared by oxidizing an alkaline solution of an iron(III) salt with concentrated chlorine bleach.〔Schreyer, J. M.; Thompson, G. W.; Ockerman, L. T. "Potassium Ferrate(VI)" Inorganic Syntheses, 1953 volume IV, pages 164-168.〕 The salt is isostructural with K2MnO4, K2SO4, and K2CrO4. The solid consists of K+ and the tetrahedral FeO42− anion, with Fe-O distances of 1.66 Å.〔Hoppe, M. L.; Schlemper, E. O.; Murmann, R. K. "Structure of Dipotassium Ferrate(VI)" Acta Crystallographica 1982, volume B38, pp. 2237-2239. .〕 The poorly soluble barium salt, BaFeO4, is also known. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「potassium ferrate」の詳細全文を読む スポンサード リンク
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