American Heritage® Dictionary of the English Language, Fourth Edition
- n. A radioactive isotope of thorium with mass number 228.
Century Dictionary and Cyclopedia
- n. A radio-element produced by the disintegration of thorium and intermediate between mesothorium, of which it is a product, and thorium emanation, of which it is the parent. It closely resembles thorium in its chemical properties, and was discovered by Hahn in 1905.
GNU Webster's 1913
- n. (Chem.) an earlier name for the thorium isotope
thorium-228, given by its discoverer Otto Hahn. It is a radioactive substance formed as one of series of products in the chain of radioactive decay of thorium. Its immediate predecessor in the chain is Actinium-228, and it decays by alpha emission to radium-224 with a half-life of 1.91 years. The name radiothoriumwas given prior to the full understanding of the nature of isotopes of elements.
- n. radioactive isotope of thorium with mass number 228
- From radio- + thorium (Wiktionary)
“Hahn's radiothorium and actinium salts also followed him to Emil Fischer's laboratory in Berlin. 30”
“Hahn had identified a new radioelement that emitted thorium emanation and which he labeled radiothorium. 28 Meanwhile, Soddy had moved to the Chemical Institute of University College in London to join Ramsay's research.”
“With Ramsay's consent, Hahn had taken with him the radiothorium he separated from samples of barium chloride and the actinium that he and a collaborator had earlier proved to be identical to the new element that the German chemist Friedrich Giesel had named emanium.”
“On this occasion, we employed the energy-rich gamma radiation of a radiothorium preparation.”
“His work here was rewarded by the discovery of a new radioactive substance, radiothorium, while working on the preparation of pure radium salts.”
“Here he discovered radioactinium and conducted investigations with Rutherford on alpha-rays of radiothorium and radioactinium.”
“Many having other radio-elements are known already, the polonium, the mesothorium, the radiothorium, the actinium.”
“Other radioactive elements have been discovered since: actinium (Debierne), radiothorium and mesothorium (Hahn), ionium (Boltwood), etc.”
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Words that sound like they might be the names of elements of the periodic table, but that aren't. Many of the words listed here were actually proposed as names for substances their creators thought...
denoting radio waves or broadcasting; connected with radioactivity; belonging to the radius
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