roentgenium(redirected from Uninunium)
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roent·gen·i·um(rĕnt-gĕn′ē-əm, -jĕn′- rŭnt-, rœnt-gen′-)
n. Symbol Rg
An artificially produced radioactive element with atomic number 111 that has only been produced in trace amounts. Its most stable known isotope has a mass number of 280 and a half-life of 3.6 seconds. See Periodic Table.
[After Wilhelm Conrad Roentgen.]
(Elements & Compounds) a synthetic radioactive element produced in small quantities by cold fusion in a linear accelerator. Symbol: Rg; atomic no: 111
[C21: named after W. K. Roentgen]
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|Noun||1.||roentgenium - a radioactive transuranic element|