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Actinium-227 is the most stable isotope of actinium, with a half-life of 21.772 years. It mainly (98.62%) undergos beta decay, but sometimes (1.38%) it will undergo alpha decay instead. [1] 227 Ac is a member of the actinium series. It is found only in traces in uranium ores – one tonne of uranium in ore contains about 0.2 milligrams of 227 Ac.
The isotope 228 Ac is a transient member of the thorium series decay chain, which begins with the parent isotope 232 Th and ends with the stable lead isotope 208 Pb. Another actinium isotope (225 Ac) is transiently present in the neptunium series decay chain, beginning with 237 Np (or 233 U) and ending with thallium (205 Tl) and near-stable ...
Actinium-225. Actinium-225 (225Ac, Ac-225) is an isotope of actinium. It undergoes alpha decay to francium-221 with a half-life of 10 days, and is an intermediate decay product in the neptunium series (the decay chain starting at 237 Np). Except for minuscule quantities arising from this decay chain in nature, 225 Ac is entirely synthetic.
Pages in category "Isotopes of actinium" ... Actinium-236 This page was last edited on 29 March 2013, at 21:29 (UTC). Text is available under the Creative ...
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 ...
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, water vapor, and inorganic acids. It forms various chemical compounds, in which protactinium is usually present in the oxidation state +5, but it can also assume +4 and even +3 or ...
The four naturally occurring isotopes allow a standard atomic weight to be given. Twenty-nine radioisotopes of protactinium have been characterized, ranging from 211 Pa to 239 Pa. The most stable isotope is 231 Pa with a half-life of 32,760 years, 233 Pa with a half-life of 26.967 days, and 230 Pa with a half-life of 17.4 days.
Radium-223 (223 Ra, Ra-223) is an isotope of radium with an 11.4-day half-life. It was discovered in 1905 by T. Godlewski, [ 2 ][ 3 ][ 4 ] a Polish chemist from Kraków, and was historically known as actinium X (AcX). [ 5 ][ 6 ] Radium-223 dichloride is an alpha particle-emitting radiotherapy drug that mimics calcium and forms complexes with ...