Razlika između verzija stranice "Borij"
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Red 89:
== Historija ==
Dvije grupe naučnika tvrdile su prvu sintezu i otkriće ovog elementa. Dokaz postojanja borija prvi je pružio sovjetski istraživački tim 1976. godine, na čelu kojeg se nalazio [[Jurij Oganesian]]. Oni su izvršili eksperiment bombardiranja mete sačinjene od izotopa [[bizmut]]a-209 i olova-208 jako ubrzanim jezgrima metala [[hrom]]a-54 i [[mangan]]a-55, respektivno.<ref name="yutsog"/> Zapažene su dvije aktivnosti, jedna sa vremenom poluraspada od jedne do dvije milisekunde, a druga sa približnim vremenom poluraspada od pet sekundi. Pošto je odnos intenziteta ove dvije aktivnosti ostao konstantan tokom cijelog eksperimenta, kasnije je donesen
Godine
:{{Su|p=209|b=83}}Bi + {{Su|p=54|b=24}}Cr → {{Su|p=262|b=107}}Bh + [[neutron|n]]
Red 99:
Godine [[1994.]] komitet [[IUPAC]]a je predložio ime borij. Ipak nesuglasice su postojale sve do [[1997.]] kada je dobio današnji naziv.
== Osobine ==
=== Izotopi ===
{{Prijevod sekcija}}
Bohrium has no stable or naturally occurring isotopes. Several radioactive isotopes have been synthesized in the laboratory, either by fusing two atoms or by observing the decay of heavier elements. Twelve different isotopes of bohrium have been reported with atomic masses 260–262, 264–267, 270–272, 274, and 278, one of which, bohrium-262, has a known [[metastable state]]. All of these but the unconfirmed <sup>278</sup>Bh decay only through alpha decay, although some unknown bohrium isotopes are predicted to undergo spontaneous fission.<ref name=nuclidetable/>
The lighter isotopes usually have shorter half-lives; half-lives of under 100 ms for <sup>260</sup>Bh, <sup>261</sup>Bh, <sup>262</sup>Bh, and <sup>262m</sup>Bh were observed. <sup>264</sup>Bh, <sup>265</sup>Bh, <sup>266</sup>Bh, and <sup>271</sup>Bh are more stable at around 1 s, and <sup>267</sup>Bh and <sup>272</sup>Bh have half-lives of about 10 s. The heaviest isotopes are the most stable, with <sup>270</sup>Bh and <sup>274</sup>Bh having measured half-lives of about 61 s and 40 s respectively, and the even heavier unconfirmed isotope <sup>278</sup>Bh appearing to have an even longer half-life of about 690 s. The unknown isotopes <sup>273</sup>Bh and <sup>275</sup>Bh are predicted to have even longer half-lives of around 90 minutes and 40 minutes respectively. Before its discovery, <sup>274</sup>Bh was also predicted to have a long half-life of 90 minutes, but it was found to have a shorter half-life of only about 40 seconds.<ref name=nuclidetable/>
The proton-rich isotopes with masses 260, 261, and 262 were directly produced by cold fusion, those with mass 262 and 264 were reported in the decay chains of meitnerium and roentgenium, while the neutron-rich isotopes with masses 265, 266, 267 were created in irradiations of actinide targets. The five most neutron-rich ones with masses 270, 271, 272, 274, and 278 (unconfirmed) appear in the decay chains of <sup>282</sup>Nh, <sup>287</sup>Mc, <sup>288</sup>Mc, <sup>294</sup>Ts, and <sup>290</sup>Fl respectively. These eleven isotopes have half-lives ranging from about ten milliseconds for <sup>262m</sup>Bh to about one minute for <sup>270</sup>Bh and <sup>274</sup>Bh, extending to about twelve minutes for the unconfirmed <sup>278</sup>Bh, one of the longest-lived known superheavy nuclides.<ref name="Doi_"/>
== Napomene ==
Line 104 ⟶ 113:
== Reference ==
{{refspisak|2|refs=
<ref name="Doi_">{{cite book|author=Münzenberg G.; Gupta M.|editor=Attila Vértes, Sándor Nagy, Zoltán Klencsár, Rezso György Lovas, Frank Rösch|title=Handbook of Nuclear Chemistry|chapter=Production and Identification of Transactinide Elements|pages=877|year=2011|doi=10.1007/978-1-4419-0720-2_19|isbn=978-1-4419-0719-6}}</ref>
<ref name=nuclidetable>{{cite web |url=http://www.nndc.bnl.gov/chart/reCenter.jsp?z=107&n=163 |title=Interactive Chart of Nuclides |publisher=Brookhaven National Laboratory |author=Sonzogni, Alejandro |location=National Nuclear Data Center |pristupdatum=26. 3. 2018}}</ref>
<ref name="262Bh">{{cite journal|author=Münzenberg G.; Hofmann S.; Heßberger F. P.; Reisdorf W. ''et al.''|year=1981|title=Identification of element 107 by α correlation chains|journal=Zeitschrift für Physik A|volume=300|issue=1|pages=107–8|doi=10.1007/BF01412623|bibcode = 1981ZPhyA.300..107M|url=https://www.researchgate.net/publication/238901044_Identification_of_Element_107_by_a_Correlation_Chains|pristupdatum=24. 12. 2016}}</ref>
<ref name="93TWG">{{Cite journal|doi=10.1351/pac199365081757|title=Discovery of the transfermium elements. Part II: Introduction to discovery profiles. Part III: Discovery profiles of the transfermium elements|year=1993|journal=Pure and Applied Chemistry|volume=65|pages=1757|author=Barber, R. C.; Greenwood N. N.; Hrynkiewicz A. Z.; Jeannin Y. P. ''et al.''|issue=8}}</ref>
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