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Protactinium is a chemical element; it has symbol Pa and atomic number 91. It is a dense, radioactive, silvery-gray actinide metal which readily reacts with oxygen ...
Protactinium(V) fluoride can be prepared by reacting protactinium oxide with either bromine pentafluoride or bromine trifluoride at about 600 °C, and protactinium(IV) fluoride is obtained from the oxide and a mixture of hydrogen and hydrogen fluoride at 600 °C; a large excess of hydrogen is required to remove atmospheric oxygen leaks into the ...
Protactinyl nitrate, protactinium(V) oxynitrate, or erroneously known as protactinium nitrate, is a radioactive chemical compound with the formula PaO(NO 3) 3 ·xH 2 O (1.5 ≤ x ≤ 4). It is a white solid that readily hydrolyzes to protactinium(V) oxide in moist air. This compound is a common commercial source of protactinium. [2]
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Protactinium(V) oxide is a chemical compound with the formula Pa 2 O 5. When it is reduced with hydrogen , it forms PaO 2 . Aristid V. Grosse was first to prepare 2 mg of Pa 2 O 5 in 1927. [ 1 ]
Protactinium(IV) oxide is a chemical compound with the formula Pa O 2. The black oxide is formed by reducing Pa 2 O 5 with hydrogen at 1 550 °C. Protactinium(IV) oxide does not dissolve in H 2 SO 4 , HNO 3 , or HCl solutions, but reacts with HF.
Protactinium-231 is the longest-lived isotope of protactinium, with a half-life of 32,760 years. In nature, it is found in trace amounts as part of the actinium series, which starts with the primordial isotope uranium-235; the equilibrium concentration in uranium ore is 46.55 231 Pa per million 235 U.
Dr John Arnold Cranston FRSE FRIC LLD (15 August 1891 – 25 April 1972) was a British research chemist. He is credited with the development of isotopes and also the co-discovery of protactinium (element 91).