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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. The actinide series, a set of 15 elements between 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 ...
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 ...
Biological roles of the elements. A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]
A biogeochemical cycle, or more generally a cycle of matter, [1] is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is ...
There are 34 known isotopes, from 203 Ac to 236 Ac, and 7 isomers. Three isotopes are found in nature, 225 Ac, 227 Ac and 228 Ac, as intermediate decay products of, respectively, 237 Np, 235 U, and 232 Th. 228 Ac and 225 Ac are extremely rare, so almost all natural actinium is 227 Ac. The most stable isotopes are 227 Ac with a half-life of 21. ...
Actinium-225 is part of the 4n +1 chain (the neptunium series). Actinium-225 has a half-life of 10 days and decays by alpha emission. It is part of the neptunium series, for it arises as a decay product of neptunium-237 and its daughters such as uranium-233 and thorium-229. It is the last nuclide in the chain with a half-life over a day until ...
Actinidine is an iridoid produced in nature by a wide variety of plants and animals. It was the first cyclopentanoid monoterpene alkaloid to be discovered. [2] It is one of several compounds that may be extracted from the valerian (Valeriana officinalis) root [3] and silver vine (Actinidia polygama), as well as several types of insects in the larval and imaginal stages. [4]