Ce4

Ce4 denotes cerium in the tetravalent oxidation state, Ce4+. Cerium is a lanthanide element (atomic number 58), and its chemistry centers on the Ce4+/Ce3+ redox couple. In many contexts, Ce4+ appears as oxidized cerium in salts or solid oxides such as ceria (CeO2). The Ce4+ state is a strong oxidant and is often less stable in aqueous solution than Ce3+.

In water, Ce4+ acts as a powerful one-electron oxidant and is readily reduced to Ce3+. It tends to hydrolyze at neutral or basic pH, forming insoluble ceric hydroxide. Stabilization is achieved by complexation with counterions or ligands. A common Ce4+ reagent is ceric ammonium nitrate, (NH4)2Ce(NO3)6, widely used as an oxidant in organic synthesis due to its strong oxidative capabilities.

Materials and catalysis: Cerium(IV) oxide, CeO2, and related ceria materials exploit the Ce4+/Ce3+ redox couple to store and release oxygen, enabling redox cycling. This oxygen storage capacity is central to the function of ceria-containing catalysts in automotive exhaust treatment and various oxidation processes. Beyond catalysis, Ce4+ salts have applications in analytical chemistry and can impart distinct coloration to glasses and coatings, reflecting the electronic transitions of Ce4+.

Occurrence and safety: Cerium occurs in minerals and is mined globally; Ce4+ is common in oxidized minerals such as cerianite. Ce4+ salts are strong oxidizers and should be handled with care to avoid contact with organic materials or incompatible substances. They are typically used under acidic or controlled conditions to limit hydrolysis and decomposition.