ceriumIV

Cerium(IV), commonly referred to as ceric, denotes the +4 oxidation state of cerium (Ce4+). In most chemical contexts, cerium(IV) compounds are strong oxidants in acidic media, and Ce4+ is readily reduced to Ce3+. The stability of Ce4+ in solution is enhanced by complexation with ligands such as nitrates, sulfates, fluorides, and chlorides, and by pairing with suitable counterions.

Common ceric reagents and compounds include ceric ammonium nitrate, (NH4)2[Ce(NO3)6], a widely used one-electron oxidant in organic synthesis and qualitative analysis. Other ceric salts, especially in acidic media (for example ceric sulfate or ceric nitrate solutions), are employed as oxidizing agents. In solid form, cerium(IV) oxide, CeO2 (ceria), is a well-known material with significant practical applications.

Cerium(IV) oxide, or ceria, crystallizes in a fluorite-type structure and exhibits rapid Ce4+/Ce3+ cycling at the oxide surface. This property makes ceria an important oxygen storage material and catalyst component. Ceria-based materials are used in automotive catalytic converters, solid oxide fuel cells, and various oxidation-cication processes. In addition to catalytic uses, ceria is employed as a polishing powder for glass and optics.

In aqueous systems, Ce4+ tends to hydrolyze and can form insoluble cerium(IV) hydroxide or oxide species at higher pH. Its strong oxidizing power is exploited to oxidize a range of substrates, especially under acidic conditions; many ceric reagents are valued for their selectivity and practical handling in laboratory and industrial settings.

Safety considerations reflect its role as a powerful oxidizer: cerium(IV) compounds can pose fire and incompatibility hazards with organic materials and reductants; handling typically requires appropriate protective equipment and containment.