highoxidation

Highoxidation is a term used in chemistry to describe substances or processes characterized by high oxidation states of elements. In practice, it refers to species where the oxidation number of a central atom is unusually large for that element within a given chemical environment. The concept is central to high-oxidation-state chemistry, a field that explores the properties, stability, and reactivity of these strongly oxidizing species.

In inorganic chemistry, high oxidation states are commonly found for certain transition metals and main-group elements in oxides, fluorides, nitrido complexes, and related compounds. Stabilization of such states often relies on ligands that strongly withdraw electron density or form robust bonds to electronegative atoms like oxygen or fluorine. Characteristics of high-oxidation-state compounds include high electrophilicity, strong oxidizing power, and a tendency to seek reduced forms.

Common examples include manganese in permanganate (MnO4−, manganese in +7), chromium in chromium trioxide CrO3 (Cr in +6), and late-transition-metal species such as osmium tetroxide OsO4 and ruthenium tetroxide RuO4 (both Os and Ru in +8). Other high-oxidation-state ions include tetra- and hepta-oxidized species like ReO4− (rethink: rhenium in +7). The exact set depends on ligands and coordination environment. High-oxidation-state species are often strong oxidants and can be sensitive to moisture or reducing agents, requiring controlled, anhydrous conditions for synthesis and handling.

Applications of high-oxidation-state chemistry span catalysis (oxidation of organic substrates), materials science (oxide catalysts and energy storage materials), and environmental chemistry (advanced oxidation processes using strong oxidants). The term is sometimes used interchangeably with high-oxidation-state chemistry, though “high oxidation state” is the more common phrasing in literature. See also oxidation state concepts.