The Schikorr reaction can be viewed as two distinct processes:
* the anaerobic oxidation of two Fe(II) (Fe) into Fe(III) (Fe) by the protons of water. The reduction of two water protons is accompanied by the production of molecular hydrogen (H), 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 (Fe → Fe + e) (oxidation of 2 iron(II) ions)
:2 (HO + e → ½ H + OH) (reduction of 2 water protons)
to give:
:2 Fe + 2 HO → 2 Fe + H + 2 OH
Adding to this reaction one intact iron(II) ion for each two oxidized iron(II) ions leads to:
:3 Fe + 2 HO → Fe + 2 Fe + H + 2 OH
Electroneutrality requires the iron cations on both sides of the equation to be counterbalanced by 6 hydroxyl anions (OH):
:3 Fe + 6 OH + 2 HO → Fe + 2 Fe + H + 8 OH
:3 Fe(OH) + 2 HO → Fe(OH) + 2 Fe(OH) + H
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 → O + HO
:acid 1 + base 2 → base 1 + acid 2, or also,
:2 OH → O + HO
it is then possible to reorganize the global reaction as:
:3 Fe(OH) + 2 HO → (FeO + HO) + (FeO + 3 HO) + H
:3 Fe(OH) + 2 HO → FeO + FeO + 4 HO + H
:3 Fe(OH) → FeO + FeO + 2 HO + H
Considering then the formation reaction of iron(II,III) oxide:
it is possible to write the balanced global reaction:
:3 Fe(OH) → (FeO·FeO) + 2 HO + H
in its final form, known as the Schikorr reaction:
:3 Fe(OH) → FeO + 2 HO + H