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Actinium is a chemical element; it has symbol Ac and atomic number 89. It was first isolated by Friedrich Oskar Giesel in 1902, who gave it the name emanium; the element got its name by being wrongly identified with a substance André-Louis Debierne found in 1899 and called actinium.
In the late 1930s, the first four actinides (actinium, thorium, protactinium, and uranium) were known. They were believed to form a fourth series of transition metals, characterized by the filling of 6 d orbitals, in which thorium, protactinium, and uranium were respective homologs of hafnium, tantalum , and tungsten. [ 2 ]
Three isotopes, 225 Ac, 227 Ac and 228 Ac, were found in nature and the others were produced in the laboratory; only the three natural isotopes are used in applications. Actinium-225 is a member of the radioactive neptunium series ; [ 60 ] it was first discovered in 1947 as a decay product of uranium-233 and it is an α-emitter with a half-life ...
Perey discovered it as a decay product of 227 Ac. [177] Francium was the last element to be discovered in nature, rather than synthesized in the lab, although four of the "synthetic" elements that were discovered later (plutonium, neptunium, astatine, and promethium) were eventually found in trace amounts in nature as well. [178]
Marguerite Catherine Perey (19 October 1909 – 13 May 1975) was a French physicist and a student of Marie Curie.In 1939, Perey discovered the element francium by purifying samples of lanthanum that contained actinium.
The actinide series is a group of chemical elements with atomic numbers ranging from 89 to 102, [note 1] including notable elements such as uranium and plutonium.The nuclides (or isotopes) thorium-232, uranium-235, and uranium-238 occur primordially, while trace quantities of actinium, protactinium, neptunium, and plutonium exist as a result of radioactive decay and (in the case of neptunium ...
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In 1899, he discovered the radioactive element actinium, as a result of continuing the work with pitchblende that the Curies had initiated. After the death of Pierre Curie in 1906, Debierne helped Marie Curie carry on and worked with her in teaching and research. In 1911, he and Marie Curie prepared radium in metallic form in visible amounts ...