| 释义 |
ionium Chem.|aɪˈəʊnɪəm|
[f. ion + -ium: see quot. 1907.]
A radioactive isotope of thorium with mass number 230, produced by the α -decay of uranium 234. Symbols Io, 230Th.
1907B. B. Boltwood in Amer. Jrnl. Sci. XXIV. 372 The name ‘Ionium’ is proposed for this new substance... This name is believed to be appropriate because of the ionizing action which it possesses in common with the other elements which emit α-radiations. 1930Engineering 4 Apr. 461/2 The elements ionium and thorium were actually found to have the same chemical properties, though differing in mass. 1954K. Rankama Isotope Geol. lxxxiii. 410 The age of deep-sea sediments younger than approximately 0·5 × 106 years may be determined from their 230Th (ionium) content. A plot of the ionium content against the depth in these sediments reveals the decay of the 80 000-year 230Th, and from this graph the age of the sediment at a given depth may be calculated... This is the ionium method for dating deep-ocean sediments. 1970Geochim. et Cosmochim. Acta XXXIV. 389 (heading) A system for detection of ionium, thorium and protactinium to date deep-sea cores. |