A radioactive isotope of thorium with mass number 230, produced by the alpha decay of uranium-234 and decaying in turn to radium-226 with a half-life of 75,000 years. Symbols Io, 230Th.
Origin
Early 20th century. From ion + -ium. With the semantic motivation, compare quot. 1907.
Definition of ionium in US English:
ionium
nounʌɪˈəʊnɪəm
Chemistry
A radioactive isotope of thorium with mass number 230, produced by the alpha decay of uranium-234 and decaying in turn to radium-226 with a half-life of 75,000 years. Symbols Io, 230Th.
Origin
Early 20th century. From ion + -ium. With the semantic motivation, compare quot. 1907.