from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An artificially produced radioactive element with atomic number 105 whose most long-lived isotopes have mass numbers of 258, 261, 262, and 263 with half-lives of 4.2, 1.8. 34, and 30 seconds, respectively. Also called unnilpentium. See Table at element.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A transuranic chemical element (symbol Db) with atomic number 105.
- n. A rejected name for rutherfordium.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a transuranic element
Since 104 was already rutherfordium, IUPAC renamed L04 dubnium, for the Russian team that claims it discovered that element years ago.
Dubna has already been enshrined in the periodic table with dubnium element 105, so the Russians chose to honor Georgi N.
The isotope with 177 neutrons decays down to dubnium (atomic number 105), whereas the isotope with 176 neutrons decays down to roentgenium (atomic number 111).