lawrencium law·ren·ci·um (lô-rěn'sē-əm, lō-)
A radioactive synthetic element produced from californium and having isotopes with mass numbers 253 through 260 and half-lives of 650 milliseconds to 3 minutes; atomic number 103.
|lawrencium (lô-rěn'sē-əm) Pronunciation Key
A synthetic, radioactive metallic element of the actinide series that is produced by bombarding californium with boron ions. Its most stable isotope is Lr 262 with a half-life of 3.6 hours. Atomic number 103. See Periodic Table.
(Lr), synthetic chemical element, the 14th member of the actinoid series of the periodic table, atomic number 103. Not occurring in nature, lawrencium (as the isotopes lawrencium-257, lawrencium-258, and lawrencium-259) was produced (1961) by Albert Ghiorso, T. Sikkeland, A.E. Larsh, and R.M. Latimer at the University of California, Berkeley, by bombarding a mixture of the longest-lived isotopes of californium (atomic number 98) with boron ions (atomic number 5) accelerated in a heavy-ion linear accelerator. A team of Soviet scientists at the Joint Institute for Nuclear Research in Dubna discovered (1965) lawrencium-256 (35-second half-life), which the Berkeley group used to show that lawrencium behaves more like the tripositive elements in the actinide series than like predominantly dipositive nobelium (atomic number 102).
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