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The Schikorr reaction formally describes the conversion of the iron(II) hydroxide (Fe(OH)2) into iron(II,III) oxide (Fe3O4). The basis of this transformation reaction was first studied by Gerhard Schikorr, a German specialist of iron corrosion, in his early works (~1928-1933) on iron(II) and iron(III) hydroxides. The global reaction that Schikorr proposed to explain his observations onto the iron hydroxides conversion, and which later received his name, can be written as follows: :3 Fe(OH)2 → Fe3O4 + H2 + 2 H2O == Reaction mechanism == The ''Schikorr reaction'' involves two distinct processes: * the anaerobic oxidation of two Fe(II) (Fe2+) into Fe(III) (Fe3+) by the protons of water. The reduction of two water protons is accompanied by the production of molecular hydrogen (H2), and; * the loss of two water molecules from the iron(II) and iron(III) hydroxides giving rise to its dehydration and to the formation of a thermodynamically more stable phase iron(II,III) oxide. The global reaction can thus be decomposed in half redox reactions as follows: :2 (Fe2+ → Fe3+ + e−) (oxidation of 2 iron(II) ions) :2 (H2O + e− → ½ H2 + OH−) (reduction of 2 water protons) to give: :2 Fe2+ + 2 H2O → 2 Fe3+ + H2 + 2 OH− Adding to this reaction one intact iron(II) ion for each two oxidized iron(II) ions leads to: :3 Fe2+ + 2 H2O → Fe2+ + 2 Fe3+ + H2 + 2 OH− Electroneutrality requires the iron cations on both sides of the equation to be counterbalanced by 6 hydroxyl anions (OH−): :3 Fe2+ + 6 OH− + 2 H2O → Fe2+ + 2 Fe3+ + H2 + 8 OH− :3 Fe(OH)2 + 2 H2O → Fe(OH)2 + 2 Fe(OH)3 + H2 For completing the main reaction, two companion reactions have still to be taken into account: The autoprotolysis of the hydroxyl anions; a proton exchange between two OH−, like in a classical acid-base reaction: :OH− + OH− → O2− + H2O :acid 1 + base 2 → base 1 + acid 2, or also, :2 OH− → O2− + H2O it is then possible to reorganize the global reaction as: :3 Fe(OH)2 + 2 H2O → (FeO + H2O) + (Fe2O3 + 3 H2O) + H2 :3 Fe(OH)2 + 2 H2O → FeO + Fe2O3 + 4 H2O + H2 :3 Fe(OH)2 → FeO + Fe2O3 + 2 H2O + H2 Considering then the formation reaction of iron(II,III) oxide: :Fe(II)O + Fe(III)2O3 → Fe3O4 it is possible to write the balanced global reaction: :3 Fe(OH)2 → (FeO·Fe2O3) + 2 H2O + H2 in its final form, known as the ''Schikorr reaction'': :3 Fe(OH)2 → Fe3O4 + 2 H2O + H2 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「Schikorr reaction」の詳細全文を読む スポンサード リンク
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