bohrium definition of bohrium in the Free Online Encyclopedia.

bohrium (bôr`ēəm), artificially produced radioactive chemical element; symbol Bh; at. no. 107; mass number of most stable isotope 262; m.p., b.p., sp. gr., and valence unknown. Situated in Group 7 of the periodic table periodic table, chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley . In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the
..... Click the link for more information. , it is expected to have properties similar to those of the rare metal rhenium rhenium (rē`nēəm), metallic chemical element; symbol Re; at. no. 75; at. wt. 186.207; m.p. about 3,180°C;; b.p.
..... Click the link for more information. .

In 1976 a Soviet team led by Y. Oganessian at the Joint Institute for Nuclear Research at Dubna bombarded bismuth-209 atoms with chromium-54 ions to produce an isotope with mass number 261 and a half-life half-life, measure of the average lifetime of a radioactive substance (see radioactivity ) or an unstable subatomic particle. One half-life is the time required for one half of any given quantity of the substance to decay.
..... Click the link for more information. of 1–2 msec. In 1981 a German research team led by P. Armbruster and G. Münzenberg at the Institute for Heavy Ion Research at Darmstadt also bombarded bismuth-209 atoms with chromium-54 ions. By reducing the temperature of the target atoms, the Germans were able to produce and unambiguously identify an isotope of element 107 having mass number 262 and a half-life of 5 msec. The Germans suggested the name nielsbohrium, which the Soviets had suggested be given to element 105 (dubnium dubnium (d
..... Click the link for more information. ), to honor the Danish physicist Niels Bohr Harald August Bohr, 1887–1951, a mathematician, taught (1915–30) at the College of Technology in Copenhagen and in 1930 became professor at the Univ. of Copenhagen. His most noted contribution to mathematics was his formulation of the theory of almost periodic functions.
..... Click the link for more information. .

In 1994 a committee of the International Union of Pure and Applied Chemistry (IUPAC), convened to resolve naming disputes for the transactinide elements transactinide elements (trăns'ăk`tənīd'), in chemistry, elements with atomic numbers greater than that of lawrencium (at.
..... Click the link for more information. , recommended that element 107 be named bohrium. While this conforms to the names of other elements honoring individuals, where only the surname is taken, it was opposed by many who were concerned that it could be confused with boron boron (bōr`ŏn) [New Gr. from borax], chemical element; symbol B; at. no. 5; at. wt. 10.81; m.p.
..... Click the link for more information. , the name for element 5. In 1997, however, the name bohrium for element 107 was recognized internationally.

See also synthetic elements synthetic elements, in chemistry, radioactive elements that were not discovered occurring in nature but as artificially produced isotopes. They are technetium (at. no. 43), which was the first element to be synthesized, promethium (at. no. 61), astatine (at. no.
..... Click the link for more information. ; transuranium elements transuranium elements, in chemistry, radioactive elements with atomic numbers greater than that of uranium (at. no. 92). All the transuranium elements of the actinide series were discovered as synthetic radioactive isotopes at the Univ.
..... Click the link for more information. .

bohrium

a transuranic element artificially produced in minute quantities by bombarding ²⁰⁴Bi atoms with ⁵⁴Cr nuclei. Symbol: Bh; atomic no.: 107

bohrium [′bȯr·ē·əm]

(chemistry)

A synthetic chemical element, symbolized Bh, atomic number 107; the fifteenth transuranium element.

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bohrium