Factors affecting the electron state of the exchange forms of iron adsorbed in layered alumosilicates

The surface of layered alumosilicates catalyzes the process of iron aggregation. At the first stage, the clay minerals adsorb $Fe^{3+}$ ions from the solution. Subsequently, under the influence of the surface subjected to various external factors, these ions aggregate into $[Fe_2^{3+}(OH)_2^-]^{4+}$ dimers and, at the next stage, they form polymeric films with a hydroxide-like structure. Under low pressures ($\sim10^7 Pa$) and under of influence of direct current, the ions and the dimers undergo the transition $Fe^{3+}\to Fe^{2+}$.