Pa2O5

Pa2O5, or protactinium pentoxide, is an inorganic compound that consists of protactinium in the +5 oxidation state combined with oxide. It is the pentoxide of protactinium and is typically formed by high-temperature oxidation of protactinium or protactinium-containing precursors. Because protactinium is highly radioactive, Pa2O5 is produced and handled only in specialized radiochemical facilities.

Pa2O5 is a refractory ceramic solid with a high melting point. It appears as a white to pale yellow powder and is insoluble in water. It dissolves in strong mineral acids to give protactinium(V) solutions. In air, the solid is relatively stable but may undergo slow surface hydrolysis in the presence of moisture, forming protactinium oxyhydroxide species on exposure.

In terms of structure, Pa2O5 forms an extended oxide network characteristic of actinide pentoxides, with the protactinium centers linked through oxide ions. The precise crystal structure can depend on synthesis conditions, but the compound is generally viewed as a stoichiometric Pa(V) oxide.

Reactivity-wise, Pa2O5 is resistant to many reagents but reacts with acids to yield soluble Pa(V) species. It is not known for widespread commercial uses, owing to the scarcity and radiological hazards of protactinium. Its primary roles are in fundamental radiochemical research and as a chemical precursor in studies of protactinium compounds and nuclear chemistry.

Safety considerations are central: Pa2O5 is radioactive and emits alpha particles. Handling requires specialized facilities, shielding, and remote manipulation to prevent ingestion, inhalation, and environmental release.