plutoniumIV

Plutonium(IV) is the chemical oxidation state of plutonium in which the element carries a formal +4 charge, often written as Pu4+. It is one of the most commonly encountered and relatively stable oxidation states of plutonium in solids and in many aqueous environments. In inorganic chemistry Pu(IV) forms a range of oxides, hydroxides and coordination compounds; plutonium dioxide (PuO2) is a prominent and stable Pu(IV) solid phase used in ceramic fuels and in immobilization of plutonium-bearing wastes.

In aqueous solution Pu4+ is prone to hydrolysis and formation of polymeric species and colloids, and it readily complexes with ligands such as carbonate, nitrate and halides. These chemical behaviors influence its mobility in the environment and its tendency to sorb onto mineral surfaces, generally reducing its solubility compared with more oxidized plutonium species. Plutonium(IV) compounds display characteristic electronic absorption features and have coordination chemistry similar to other actinide(IV) ions.

Because plutonium is radioactive and chemically toxic, compounds containing Pu(IV) are handled under strict regulatory and radiological controls. In the nuclear industry, Pu(IV) chemistry is relevant to fuel fabrication (notably mixed oxide fuels containing PuO2), waste management and chemical separation processes, where control of oxidation state affects extraction and stabilization. Environmental and health considerations drive research into the speciation, transport and long-term behavior of Pu(IV) in natural and engineered systems.