Description
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Protactinium is an actinide that has a bright silver metallic appearance in its natural solid state. It is highly radioactive, very toxic, and one of the rarest elements on earth. At extremely low temperatures it displays superconductivity traits. Protactinium has an atomic weight of 231.03588, a melting point of 2854 °F, and the boiling point of this element is not yet known. The rarity, toxicity, and radioactivity of protactinium prevent it from being used for any commercial uses; it is currently only used for research purposes.
Isolation
Protactinium occurs in nature in pitchblende from the decay of uranium. Isolation of protactinium is not normally carried out as it is expensive and dangerous.
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Protactinium has been isolated and synthesized rarely throughout its history. It was discovered in 1913 and prepared in 1927. The first process that was used to isolate protactinium was carried out by Aristid Grosse. He reduced protactinium to an oxide form, and then converted the oxide form to an iodide. Using a high vacuum and an electrically heated filament, he ‘cracked’ the iodide form of protactinium to yield pure protactinium and iodide gas. Protactinium was also produced by the Atomic Energy Authority of the United Kingdom. The isolation process was extremely complicated, produced 60 tons of waste material, cost over ½ a million dollars, and resulted in only 125 grams of protactinium. The half life of protactinium is extremely short, some isotopes have half lives of less than 1.8 seconds, and so it is difficult to produce and store. The hazardous pure form of protactinium must be handled with cautions that are similar to plutonium.