ThoriumIV

Thorium(IV), abbreviated Th4+, refers to thorium in the tetravalent oxidation state as it occurs in chemical species. The designation thoriumIV is commonly used to denote compounds in which thorium carries a +4 charge, including salts, oxides, and coordination complexes.

Thorium is a heavy, radioactive actinide. The most abundant isotope, 232Th, is long-lived. In its +4 state the ion is highly charged and behaves as a hard Lewis acid. In aqueous solution Th4+ undergoes rapid hydrolysis, forming various hydroxy and oxo species and, at higher pH, polymeric or colloidal species.

Coordination chemistry: Th4+ readily binds to oxygen donors such as oxides, hydroxides, carbonates, and fluorides. In solids, thorium forms the insoluble oxide ThO2, as well as various thorium halides and nitrates. Its complexes tend to feature high coordination numbers and extensive bridging by oxide or hydroxy ligands.

Occurrence and applications: Thorium occurs in trace minerals such as monazite and thorite. Historically, thorium oxide was used in gas mantles and other high-temperature applications. In modern contexts, Th-232 is of interest for potential use as a fertile material in nuclear fuel cycles, though practical deployment is limited by radioactivity, regulatory, and economic considerations.

Safety: As a radioactive substance, thorium(IV) compounds emit alpha particles and require appropriate shielding and waste management. Handling typically involves specialized facilities and regulatory compliance.