from The American Heritage® Dictionary of the English Language, 5th Edition.
- noun A synthetic transuranic metallic element having over 20 isotopes and isomers with mass numbers ranging from 242 to 260. The longest-lived isotope has mass number 257 and a half-life of approximately 100 days. Atomic number 100; melting point 1527°C; valence 3. cross-reference: Periodic Table.
from the GNU version of the Collaborative International Dictionary of English.
- noun the transuranic element of atomic number 100; symbol Fm. The atomic weight of the most stable isotope, having a half-life of about 80 days, is 257. The first isotope, Fm255 was discovered in 1952 in the debris of a thermonuclear explosion. Other istopes have been produced in nuclear reactors and by decay of other transuranic elements.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun A
transuranicchemical element (symbol Fm) with an atomic numberof 100.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- noun a radioactive transuranic metallic element produced by bombarding plutonium with neutrons
from The American Heritage® Dictionary of the English Language, 4th Edition
from Wiktionary, Creative Commons Attribution/Share-Alike License
The first glimpse at 112 lasted for only a third of a millisecond, until it decayed first into element 110 (darmstaditium) and then into four different short-lived elements until researchers lost its trail at element 110 (fermium).