m, -jen-, ruhnt-] 
| a super-heavy, synthetic radioactive element. Symbol: Rg; atomic number: 111. |
roent·gen·i·um  (rěnt-gěn'ē-əm, -jěn'-, rŭnt-, rɶnt-gěn'-) n. Symbol Rg An artificially produced radioactive element with atomic number 111 and a mass number of 280, whose most stable known isotope has a half-life of 3.6 seconds. See Table at element. [After Wilhelm Konrad Roentgen.] |
