lawrencium

law·ren·ci·um   (lô-rěn'sē-əm, lō-)    n.   Symbol Lr A short-lived, radioactive synthetic transuranic element produced from californium and whose most stable isotope has a mass number of 262 with a half-life of 3.6 hours; atomic number 103. See Table at element. [After Ernest Orlando Lawrence.]

Main Entry: law·ren·ci·um
Pronunciation: lo-'ren(t)-sE-&m
Function: noun
: a short-lived radioactive element that is producedartificially from californium —symbol Lr; —see ELEMENT table
Lawárence /'lor-&n(t)s,'lär-,/ Ernest Orlando (1901–1958), American physicist. Lawrence was associated with the University of California, Berkeley, for virtually all of his research career. Hewas responsible for the establishment of the Radiation Laboratory at Berkeley and was appointed its director in 1936. He first conceived of the cyclotron, a subatomic particle accelerator, in 1929, andin 1939 he was awarded the Nobel Prize for Physics for its invention. Using the cyclotron Lawrence produced radioactive phosphorus and other isotopes for medical use, including iodine for the firsttherapeutic treatment of hyperthyroidism. In 1961 element 103 was named lawrencium in his honor by scientists at the Lawrence Radiation Laboratory at Berkeley.

lawrencium law·ren·ci·um (lô-rěn'sē-əm, lō-)
n.
Symbol Lr
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  Symbol Lr 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.

lawrencium

(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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