disproportionatie

Disproportionation is a redox reaction in which a species in a given oxidation state reacts to form two products that contain the same element in different oxidation states. The process involves the element undergoing simultaneous oxidation and reduction. Disproportionation generally occurs for species that are in an intermediate oxidation state and is influenced by factors such as pH, temperature, and the presence of catalysts or ligands. It is the opposite of comproportionation, in which two species with different oxidation states react to form a single intermediate state.

Common examples illustrate the concept. Hydrogen peroxide disproportionates: 2 H2O2 → 2 H2O + O2. Hypochlorite disproportionates under certain aqueous conditions to give chloride and chlorate: 3 ClO− → Cl− + ClO3−. Permanganate can disproportionate in acidic solution to yield both Mn2+ and MnO2: 3 MnO4− + 4 H+ → 2 Mn2+ + MnO2 + 2 H2O.

Disproportionation has relevance in environmental chemistry and inorganic synthesis. It can affect the stability and speciation of oxidants and reductants, influence corrosion and water treatment processes, and play a role in redox cycling and analytical methods. Understanding the tendency of a species to disproportionate helps in predicting reaction pathways and designing conditions for desired redox outcomes.