The net result of this reaction is the removal of one or more electrons from a compound, which causes the structure to be less rigid and increasingly unstable. The most common oxides are those of iron and aluminum, and their respective red and yellow staining of soils is quite common in tropical regions which have high temperatures and precipitation. Reduction is simply the reverse of oxidation, and is thus caused by the addition of one or more electrons producing a more stable compound. In many situations the H and OH ions become a structural part of the crystal lattice of the mineral. Hydration also allows for the acceleration of other decompositional reactions by expanding the crystal lattice offering more surface area for reaction.
Carbonation is the reaction of carbonate and bicarbonate ions with minerals.
The formation of carbonates usually takes place as a result of other chemical processes. Carbonation is especially active when the reaction environment is abundant with carbon dioxide. The formation of carbonic acid, a product of carbon dioxide and water, is important in the solution of carbonates and the decomposition of mineral surfaces because of its acidic nature. Water and the ions it carries as it moves through and around rocks and minerals can further the weathering process. Geomorphologists call this phenomena solution .