Noun
a short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead
Source: WordNetAnalysis of the relative concentrations of various uranium, thorium and protactinium isotopes in water and minerals is used in radiometric dating of sediments which are up to 175,000 years old and in modeling of various geological processes. Source: Internet
Among those, most remarkable is Na 3 PaF 8 where protactinium ion is symmetrically surrounded by 8 F − ions which form a nearly perfect cube. Source: Internet
As protactinium is present in small amounts in most natural products and materials, it is ingested with food or water and inhaled with air. Source: Internet
Before the advent of nuclear reactors, protactinium was separated for scientific experiments from uranium ores. Source: Internet
As with oxides, protactinium forms mixed halides with alkali metals. Source: Internet
An alternative reaction is between protactinium pentachloride and hydrogen bromide or thionyl bromide. Source: Internet