View source for Physics:Isotopes of bohrium

{{Short description|Nuclides with atomic number of 107 but with different mass numbers}}
{{infobox bohrium isotopes}}
[[Chemistry:Bohrium|Bohrium]] (<sub>107</sub>Bh) is an artificial element. Like all artificial elements, it has no [[Physics:Stable isotope|stable isotope]]s, and a [[Physics:Standard atomic weight|standard atomic weight]] cannot be given. The first [[Physics:Isotope|isotope]] to be synthesized was <sup>262</sup>Bh in 1981. There are 11 known isotopes ranging from <sup>260</sup>Bh to <sup>274</sup>Bh, and 1 [[Physics:Nuclear isomer|isomer]], <sup>262m</sup>Bh. The longest-lived isotope is <sup>270</sup>Bh with a [[Physics:Half-life|half-life]] of 2.4 minutes, although the unconfirmed <sup>278</sup>Bh may have an even longer half-life of about 690&nbsp;seconds.

== List of isotopes ==
{{Isotopes table
|symbol=Bh
|refs=<!-- not NUBASE2016 yet (2019-07-14) -->
|notes=m, unc(), mass#, spin(), SF
}}
|-
| <sup>260</sup>Bh<ref>{{cite journal |last1=Nelson |first1=S. L. |last2=Gregorich |first2=K. E. |last3=Dragojević |first3=I. |last4=Garcia |first4=M. A. |last5=Gates |first5=J. M. |last6=Sudowe |first6=R. |last7=Nitsche |first7=H. |title=Lightest Isotope of Bh Produced via the 209Bi(52Cr,n)260Bh Reaction |journal=Physical Review Letters |date=14 January 2008 |volume=100 |issue=2 |pages=022501 |doi=10.1103/PhysRevLett.100.022501 |pmid=18232860 |bibcode=2008PhRvL.100b2501N |s2cid=1242390 |url=https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.100.022501 |access-date=2 July 2023}}</ref>
| style="text-align:right" | 107
| style="text-align:right" | 153
| 260.12166(26)#
| 41(14) ms<br/>[{{val|35|19|9|u=ms}}]
| [[Physics:Alpha decay|α]]
| <sup>256</sup>Db
|
|-
| rowspan=2|<sup>261</sup>Bh<ref>{{cite journal |last1=Kondev |first1=F. G. |last2=Wang |first2=M. |last3=Huang |first3=W. J. |last4=Naimi |first4=S. |last5=Audi |first5=G. |title=The NUBASE2020 evaluation of nuclear physics properties * |journal=Chinese Physics C, High Energy Physics and Nuclear Physics |date=1 March 2021 |volume=45 |issue=3 |page=030001 |doi=10.1088/1674-1137/abddae |bibcode=2021ChPhC..45c0001K |osti=1774641 |language=English |issn=1674-1137|doi-access=free }}</ref>
| rowspan=2 style="text-align:right" | 107
| rowspan=2 style="text-align:right" | 154
| rowspan=2|261.121400(190)<ref>[https://iopscience.iop.org/article/10.1088/1674-1137/abddaf/pdf AME 2020 atomic mass evaluation]</ref>
| rowspan=2|12.8(3.2) ms<br/>[{{val|11.8|3.9|2.4|u=ms}}]
| α
| <sup>257</sup>Db
| rowspan=2|(5/2−)
|-
| [[Physics:Spontaneous fission|SF]] (rare)
| (various)
|-
| rowspan=3|<sup>262</sup>Bh<ref>{{cite journal |last1=Streicher |first1=B. |title=Synthesis and spectroscopic properties of transfermium isotopes with Z = 105, 106 and 107 |date=1 July 2006 |url=https://www.osti.gov/etdeweb/biblio/21555013 |access-date=2 July 2023 |language=English}}</ref>
| rowspan=3 style="text-align:right" | 107
| rowspan=3 style="text-align:right" | 155
| rowspan=3|262.122650(100)<ref>[https://iopscience.iop.org/article/10.1088/1674-1137/abddaf/pdf AME 2020 atomic mass evaluation]</ref>
| rowspan=3|{{val|135|15|12|u=ms}}
| α (>94.9%)
| <sup>258</sup>Db
| rowspan=3|
|-
| [[Physics:Beta decay|β<sup>+</sup>]] (<3.0%)
| <sup>262</sup>Sg
|-
| SF (2.1%)
| (various)
|-
| style="text-indent:1em" | <sup>262m</sup>Bh
| colspan="3" style="text-indent:2em" | 220(50)&nbsp;keV
| {{val|13.2|1.2|1.0|u=ms}}
| α
| <sup>258</sup>Db
| 
|-
| rowspan=2|<sup>264</sup>Bh
| rowspan=2 style="text-align:right" | 107
| rowspan=2 style="text-align:right" | 157
| rowspan=2|264.12459(19)#
| rowspan=2|1.07(21)&nbsp;s
| α (85%)
| <sup>260</sup>Db
| rowspan=2|
|-
| SF(β<sup>+</sup>?) (15%)<ref>{{cite journal |last1=Morita |first1=K. |last2=Morimoto |first2=K. |last3=Kaji |first3=D. |last4=Haba |first4=H. |last5=Ideguchi |first5=E. |last6=C. Peter |first6=J. |last7=Kanungo |first7=R. |last8=Katori |first8=K. |last9=Koura |first9=H. |last10=Kudo |first10=H. |last11=Ohnishi |first11=T. |last12=Ozawa |first12=A. |last13=Suda |first13=T. |last14=Sueki |first14=K. |last15=Tanihata |first15=I. |last16=Xu |first16=H. |last17=V. Yeremin |first17=A. |last18=Yoneda |first18=A. |last19=Yoshida |first19=A. |last20=Zhao |first20=Y.-L. |last21=Zheng |first21=T. |last22=Goto |first22=S. |last23=Tokanai |first23=F. |title=Production and Decay Properties of 272 111 and its Daughter Nuclei |journal=Journal of the Physical Society of Japan |date=15 July 2004 |volume=73 |issue=7 |pages=1738–1744 |doi=10.1143/JPSJ.73.1738 |bibcode=2004JPSJ...73.1738M |url=https://journals.jps.jp/doi/abs/10.1143/JPSJ.73.1738 |access-date=2 July 2023 |language=en |issn=0031-9015}}</ref>
| (various)
|-
| <sup>265</sup>Bh<ref>{{cite journal |last1=Gan |first1=Z. G. |last2=Guo |first2=J. S. |last3=Wu |first3=X. L. |last4=Qin |first4=Z. |last5=Fan |first5=H. M. |last6=Lei |first6=X. G. |last7=Liu |first7=H. Y. |last8=Guo |first8=B. |last9=Xu |first9=H. G. |last10=Chen |first10=R. F. |last11=Dong |first11=C. F. |last12=Zhang |first12=F. M. |last13=Wang |first13=H. L. |last14=Xie |first14=C. Y. |last15=Feng |first15=Z. Q. |last16=Zhen |first16=Y. |last17=Song |first17=L. T. |last18=Luo |first18=P. |last19=Xu |first19=H. S. |last20=Zhou |first20=X. H. |last21=Jin |first21=G. M. |last22=Ren |first22=Zhongzhou |title=New isotope 265Bh |journal=The European Physical Journal A - Hadrons and Nuclei |date=1 June 2004 |volume=20 |issue=3 |pages=385–387 |doi=10.1140/epja/i2004-10020-2 |bibcode=2004EPJA...20..385G |s2cid=120622108 |url=https://link.springer.com/article/10.1140/epja/i2004-10020-2 |access-date=2 July 2023 |language=en |issn=1434-601X}}</ref>
| style="text-align:right" | 107
| style="text-align:right" | 158
| 265.12491(25)#
| 1.19(52)&nbsp;s<br/>[{{val|0.94|0.70|0.31|u=s}}]
| α
| <sup>261</sup>Db
|
|-
| rowspan=2|<sup>266</sup>Bh
| rowspan=2 style="text-align:right" | 107
| rowspan=2 style="text-align:right" | 159
| rowspan=2|266.12679(18)#
| rowspan=2|{{val|10.0|2.6|1.7|u=s}}<ref>{{cite journal |last1=Haba |first1=H. |last2=Fan |first2=F. |last3=Kaji |first3=D. |last4=Kasamatsu |first4=Y. |last5=Kikunaga |first5=H. |last6=Komori |first6=Y. |last7=Kondo |first7=N. |last8=Kudo |first8=H. |last9=Morimoto |first9=K. |last10=Morita |first10=K. |last11=Murakami |first11=M. |last12=Nishio |first12=K. |last13=Omtvedt |first13=J. P. |last14=Ooe |first14=K. |last15=Qin |first15=Z. |last16=Sato |first16=D. |last17=Sato |first17=N. |last18=Sato |first18=T. K. |last19=Shigekawa |first19=Y. |last20=Shinohara |first20=A. |last21=Takeyama |first21=M. |last22=Tanaka |first22=T. |last23=Toyoshima |first23=A. |last24=Tsukada |first24=K. |last25=Wakabayashi |first25=Y. |last26=Wang |first26=Y. |last27=Wulff |first27=S. |last28=Yamaki |first28=S. |last29=Yano |first29=S. |last30=Yasuda |first30=Y. |last31=Yokokita |first31=T. |title=Production of 266Bh in the 248Cm(23Na,5n)266Bh reaction and its decay properties |journal=Physical Review C |date=27 August 2020 |volume=102 |issue=2 |pages=024625 |doi=10.1103/PhysRevC.102.024625 |bibcode=2020PhRvC.102b4625H |url=https://journals.aps.org/prc/abstract/10.1103/PhysRevC.102.024625 |access-date=2 July 2023|hdl=1885/270010 |s2cid=225191147 |hdl-access=free }}</ref>
| α
| <sup>262</sup>Db
| rowspan=2|
|-
| β<sup>+</sup>?
| <sup>266</sup>Sg
|-
| <sup>267</sup>Bh
| style="text-align:right" | 107
| style="text-align:right" | 160
| 267.12750(28)#
| 22(10)&nbsp;s<br/>[{{val|17|14|6|u=s}}]
| α
| <sup>263</sup>Db
|
|-
| <sup>270</sup>Bh<ref group="n">Not directly synthesized, occurs in decay chain of <sup>282</sup>Nh</ref>
| style="text-align:right" | 107
| style="text-align:right" | 163
| 270.13336(31)#
| {{val|2.4|4.4|0.9|u=min}}<ref name=Mc2022>{{Cite journal |title=New isotope <sup>286</sup>Mc produced in the <sup>243</sup>Am+<sup>48</sup>Ca reaction |last1=Oganessian |first1=Yu. Ts. |last2=Utyonkov |first2=V. K. |last3=Kovrizhnykh |first3=N. D. |display-authors=et al. |date=2022 |journal=Physical Review C |volume=106 |number=64306 |page=064306 |doi=10.1103/PhysRevC.106.064306|bibcode=2022PhRvC.106f4306O |s2cid=254435744 |doi-access=free }}</ref>
| α
| <sup>266</sup>Db
|
|-
| <sup>271</sup>Bh<ref group="n">Not directly synthesized, occurs in decay chain of <sup>287</sup>Mc</ref>
| style="text-align:right" | 107
| style="text-align:right" | 164
| 271.13526(48)#
| {{val|2.9|2.2|0.9|u=s}}<ref name=Mc2022/>
| α
| <sup>267</sup>Db
| 
|-
| <sup>272</sup>Bh<ref group="n">Not directly synthesized, occurs in decay chain of <sup>288</sup>Mc</ref>
| style="text-align:right" | 107
| style="text-align:right" | 165
| 272.13826(58)#
| {{val|8.8|(7)|u=s}}<ref name=Mc2022/>
| α
| <sup>268</sup>Db
|
|-
| <sup>274</sup>Bh<ref group="n">Not directly synthesized, occurs in decay chain of <sup>294</sup>Ts</ref>
| style="text-align:right" | 107
| style="text-align:right" | 167
| 274.14355(65)#
| 57(27)&nbsp;s<br/>[{{val|44|34|13|u=s}}]<ref>{{cite journal |last1=Kondev |first1=F. G. |last2=Wang |first2=M. |last3=Huang |first3=W. J. |last4=Naimi |first4=S. |last5=Audi |first5=G. |title=The NUBASE2020 evaluation of nuclear physics properties * |journal=Chinese Physics C, High Energy Physics and Nuclear Physics |date=1 March 2021 |volume=45 |issue=3 |page=030001 |doi=10.1088/1674-1137/abddae |bibcode=2021ChPhC..45c0001K |osti=1774641 |language=English |issn=1674-1137|doi-access=free }}</ref>
| α
| <sup>270</sup>Db
|
|-
| <sup>278</sup>Bh<ref group="n">Not directly synthesized, occurs in decay chain of <sup>290</sup>Fl and <sup>294</sup>Lv; unconfirmed</ref>
| style="text-align:right" | 107
| style="text-align:right" | 171
|
| 11.5&nbsp;min?
| SF
| (various)
|
{{Isotopes table/footer}}

==Nucleosynthesis==
[[Physics:Superheavy element|Superheavy element]]s such as bohrium are produced by bombarding lighter elements in [[Physics:Particle accelerator|particle accelerator]]s that induce fusion reactions. Whereas most of the isotopes of bohrium can be synthesized directly this way, some heavier ones have only been observed as decay products of elements with higher [[Physics:Atomic number|atomic number]]s.<ref name="AM89">{{Cite journal |first1=Peter |last1=Armbruster |name-list-style=amp|first2=Gottfried|last2=Münzenberg |title=Creating superheavy elements |journal=Scientific American |volume=34 |pages=36–42 |year=1989}}</ref>

Depending on the energies involved, the former are separated into "hot" and "cold". In hot fusion reactions, very light, high-energy projectiles are accelerated toward very heavy targets ([[Chemistry:Actinide|actinide]]s), giving rise to compound nuclei at high excitation energy (~40–50−[[Physics:Electronvolt|MeV]]) that may either fission or evaporate several (3 to 5) neutrons.<ref name="fusion">{{cite journal |last1=Barber |first1=Robert C. |last2=Gäggeler |first2=Heinz W. |last3=Karol |first3=Paul J. |last4=Nakahara |first4=Hiromichi |last5=Vardaci |first5=Emanuele |last6=Vogt |first6=Erich |title=Discovery of the element with atomic number 112 (IUPAC Technical Report) |journal=Pure and Applied Chemistry |volume=81 |issue=7 |page=1331 |year=2009 |doi=10.1351/PAC-REP-08-03-05|doi-access=free }}</ref> In cold fusion reactions, the produced fused nuclei have a relatively low excitation energy (~10–20&nbsp;MeV), which decreases the probability that these products will undergo fission. As the fused nuclei cool to the [[Physics:Ground state|ground state]], they require emission of only one or two neutrons, thus allowing for the generation of more neutron-rich products.<ref name="AM89" /> The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see [[Physics:Cold fusion|cold fusion]]).<ref>{{cite journal |last1=Fleischmann |first1=Martin |last2=Pons |first2=Stanley |year=1989 |title=Electrochemically induced nuclear fusion of deuterium |journal=Journal of Electroanalytical Chemistry and Interfacial Electrochemistry |volume=261 |issue=2 |pages=301–308 |doi=10.1016/0022-0728(89)80006-3 }}</ref>

The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with ''Z'' = 107.

{|class="wikitable" style="text-align:center"
! Target !! Projectile !! CN !! Attempt result
|-
!<sup>208</sup>Pb
|<sup>55</sup>Mn||<sup>263</sup>Bh||{{Yes|Successful reaction}}
|-
!<sup>209</sup>Bi
|<sup>54</sup>Cr||<sup>263</sup>Bh||{{Yes|Successful reaction}}
|-
!<sup>209</sup>Bi
|<sup>52</sup>Cr||<sup>261</sup>Bh||{{Yes|Successful reaction}}
|-
!<sup>238</sup>U
|<sup>31</sup>P||<sup>269</sup>Bh||{{Yes|Successful reaction}}
|-
!<sup>243</sup>Am
|<sup>26</sup>Mg||<sup>269</sup>Bh||{{Yes|Successful reaction}}
|-
!<sup>248</sup>Cm
|<sup>23</sup>Na||<sup>271</sup>Bh||{{Yes|Successful reaction}}
|-
!<sup>249</sup>Bk
|<sup>22</sup>Ne||<sup>271</sup>Bh||{{Yes|Successful reaction}}
|}

===Cold fusion===
Before the first successful synthesis of hassium in 1981 by the GSI team, the synthesis of bohrium was first attempted in 1976 by scientists at the [[Organization:Joint Institute for Nuclear Research|Joint Institute for Nuclear Research]] at [[Organization:Dubna|Dubna]] using this cold fusion reaction. They detected two [[Physics:Spontaneous fission|spontaneous fission]] activities, one with a [[Physics:Half-life|half-life]] of 1–2&nbsp;ms and one with a half-life of 5&nbsp;s. Based on the results of other cold fusion reactions, they concluded that they were due to <sup>261</sup>Bh and <sup>257</sup>Db respectively. However, later evidence gave a much lower SF branching for <sup>261</sup>Bh reducing confidence in this assignment. The assignment of the dubnium activity was later changed to <sup>258</sup>Db, presuming that the decay of bohrium was missed. The 2 ms SF activity was assigned to <sup>258</sup>Rf resulting from the 33% [[Physics:Electron capture|EC]] branch. The GSI team studied the reaction in 1981 in their discovery experiments. Five atoms of <sup>262</sup>Bh were detected using the method of correlation of genetic parent-daughter decays.<ref name="262Bh">{{cite journal|last1=Münzenberg|first1=G.|last2=Hofmann|first2=S.|last3=Heßberger|first3=F.P.|last4=Reisdorf|first4=W.|last5=Schmidt|first5=K.H.|last6=Schneider|first6=J.H.R.|last7=Armbruster|first7=P.|last8=Sahm|first8=C.C.|last9=Thuma|first9=B.|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|url=http://www-alt.gsi.de/forschung/kp/kp2/ship/107-discovery.pdf|archive-url=https://wayback.archive-it.org/all/20120712210319/http://www-alt.gsi.de/forschung/kp/kp2/ship/107-discovery.pdf|url-status=dead|archive-date=2012-07-12|bibcode=1981ZPhyA.300..107M|s2cid=118312056 |access-date=19 November 2012}}</ref> In 1987, an internal report from Dubna indicated that the team had been able to detect the [[Physics:Spontaneous fission|spontaneous fission]] of <sup>261</sup>Bh directly. The GSI team further studied the reaction in 1989 and discovered the new isotope <sup>261</sup>Bh during the measurement of the 1n and 2n excitation functions but were unable to detect an SF branching for <sup>261</sup>Bh.<ref name="261Bh">{{cite journal|doi=10.1007/BF01565147|title=Element 107|year=1989 |last1=Münzenberg |first1=G.| journal=Zeitschrift für Physik A|volume=333|pages=163–175
|last2=Armbruster|first2=P.|last3=Hofmann|first3=S.|last4=Heßberger|first4=F. P.|last5=Folger|first5=H.|last6=Keller|first6=J. G.|last7=Ninov|first7=V.|last8=Poppensieker|first8=K.|last9=Quint|first9=A. B.
|last10=Reisdorf|first10=W.|last11=Schmidt|first11=K.-H.|last12=Schneider|first12=J. R. H.|last13=Schött|first13=H.-J.|last14=Sümmerer|first14=K.|last15=Zychor|first15=I.|last16=Leino|first16=M. E.|last17=Ackermann|first17=D.|last18=Gollerthan|first18=U.|last19=Hanelt|first19=E.|last20=Morawek|first20=W.|last21=Vermeulen|first21=D.|last22=Fujita|first22=Y.|last23=Schwab|first23=T.|issue=2|bibcode = 1989ZPhyA.333..163M |s2cid=186231905 |display-authors=8}}</ref> They continued their study in 2003 using newly developed [[Chemistry:Bismuth(III) fluoride|bismuth(III) fluoride]] (BiF<sub>3</sub>) targets, used to provide further data on the decay data for <sup>262</sup>Bh and the daughter <sup>258</sup>Db. The 1n excitation function was remeasured in 2005 by the team at the [[Organization:Lawrence Berkeley National Laboratory|Lawrence Berkeley National Laboratory]] (LBNL) after some doubt about the accuracy of previous data. They observed 18 atoms of <sup>262</sup>Bh and 3 atoms of <sup>261</sup>Bh and confirmed the two isomers of <sup>262</sup>Bh.<ref>[http://rnc.lbl.gov/nsd/annualreport2005/contributions/Nelson_LE.pdf "Entrance Channel Effects in the Production of <sup>262,261</sup>Bh"], Nelson et al., ''LBNL repositories 2005''. Retrieved 2008-03-04</ref>

In 2007, the team at LBNL studied the analogous reaction with chromium-52 projectiles for the first time to search for the lightest bohrium isotope <sup>260</sup>Bh:

:{{nuclide|link=yes|bismuth|209}} + {{nuclide|link=yes|chromium|52}} → {{nuclide|link=yes|bohrium|260}} + {{SubatomicParticle|link=yes|neutron}}

The team successfully detected 8 atoms of <sup>260</sup>Bh decaying by [[Physics:Alpha decay|alpha decay]] to <sup>256</sup>Db, emitting alpha particles with energy 10.16&nbsp;[[Physics:Electronvolt|MeV]]. The alpha decay energy indicates the continued stabilizing effect of the [[Physics:Neutron number|N]]=152 closed shell.<ref name="260Bh">{{cite journal|last1=Nelson|first1=S.|last2=Gregorich|first2=K.|last3=Dragojević|first3=I.|last4=Garcia|first4=M.|last5=Gates|first5=J.|last6=Sudowe|first6=R.|last7=Nitsche|first7=H.|title=Lightest Isotope of Bh Produced via the Bi209(Cr52,n)Bh260 Reaction|journal=Physical Review Letters|volume=100|year=2008|doi=10.1103/PhysRevLett.100.022501|issue=2|pages=22501|bibcode=2008PhRvL.100b2501N|pmid=18232860|s2cid=1242390 }}</ref>

The team at Dubna also studied the reaction between lead-208 targets and manganese-55 projectiles in 1976 as part of their newly established cold fusion approach to new elements:

:{{nuclide|link=yes|lead|208}} + {{nuclide|link=yes|manganese|55}} → {{nuclide|link=yes|bohrium|262}} + {{SubatomicParticle|link=yes|neutron}}

They observed the same spontaneous fission activities as those observed in the reaction between bismuth-209 and chromium-54 and again assigned them to <sup>261</sup>Bh and <sup>257</sup>Db. Later evidence indicated that these should be reassigned to <sup>258</sup>Db and <sup>258</sup>Rf (see above). In 1983, they repeated the experiment using a new technique: measurement of alpha decay from a [[Physics:Decay product|decay product]] that had been separated out chemically. The team were able to detect the alpha decay from a decay product of <sup>262</sup>Bh, providing some evidence for the formation of bohrium nuclei. This reaction was later studied in detail using modern techniques by the team at LBNL. In 2005 they measured 33 decays of <sup>262</sup>Bh and 2 atoms of <sup>261</sup>Bh, providing an [[Physics:Excitation function|excitation function]] for the reaction emitting one [[Physics:Neutron|neutron]] and some spectroscopic data of both <sup>262</sup>Bh isomers. The excitation function for the reaction emitting two neutrons was further studied in a 2006 repeat of the reaction. The team found that the reaction emitting one neutron had a higher [[Physics:Cross section|cross section]] than the corresponding reaction with a <sup>209</sup>Bi target, contrary to expectations. Further research is required to understand the reasons.<ref>{{cite journal|title=Excitation function for the production of <sup>262</sup>Bh (Z=107) in the odd-Z-projectile reaction <sup>208</sup>Pb(<sup>55</sup>Mn, n)|doi=10.1103/PhysRevC.73.014611|year=2006|author=Folden Iii, C. M.|journal=Physical Review C|volume=73|issue=1|pages=014611|bibcode = 2006PhRvC..73a4611F |last2=Nelson|last3=Düllmann|last4=Schwantes|last5=Sudowe|last6=Zielinski|last7=Gregorich|last8=Nitsche|last9=Hoffman|s2cid=73712859 |url=https://zenodo.org/record/1233773}}</ref><ref>[http://repositories.cdlib.org/cgi/viewcontent.cgi?article=3948&context=lbnl "Excitation function for the production of <sup>262</sup>Bh (Z=107) in the odd-Z-projectile reaction <sup>208</sup>Pb(<sup>55</sup>Mn, n)"], Folden et al., ''LBNL repositories'', May 19, 2005. Retrieved on 2008-02-29</ref>

===Hot fusion===
The reaction between [[Physics:Uranium-238|uranium-238]] targets and [[Chemistry:Phosphorus|phosphorus]]-31 projectiles was first studied in 2006 at the LBNL as part of their systematic study of fusion reactions using uranium-238 targets:

:{{nuclide|link=yes|uranium|238}} + {{nuclide|link=yes|phosphorus|31}} → {{nuclide|link=yes|bohrium|264}} + 5 {{SubatomicParticle|link=yes|neutron}}

Results have not been published but preliminary results appear to indicate the observation of [[Physics:Spontaneous fission|spontaneous fission]], possibly from <sup>264</sup>Bh.<ref>[http://www-wnt.gsi.de/tasca06/images/contributions/TASCA_06_Gates.pdf Hot fusion studies at the BGS with light projectiles and 238U targets] {{webarchive|url=https://web.archive.org/web/20110719033456/http://www-wnt.gsi.de/tasca06/images/contributions/TASCA_06_Gates.pdf |date=2011-07-19 }}, J. M. Gates</ref>

Recently, the team at the Institute of Modern Physics (IMP), Lanzhou, have studied the nuclear reaction between [[Physics:Americium-243|americium-243]] targets and accelerated nuclei of [[Chemistry:Magnesium|magnesium]]-26 in order to synthesise the new isotope <sup>265</sup>Bh and gather more data on <sup>266</sup>Bh:

:{{nuclide|link=yes|americium|243}} + {{nuclide|link=yes|magnesium|26}} → {{nuclide|bohrium|269−x}} + x {{SubatomicParticle|link=yes|neutron}} (x = 3, 4, or 5)

In two series of experiments, the team measured partial excitation functions for the reactions emitting three, four, and five neutrons.<ref name="265Bh">{{cite journal|title=New isotope <sup>265</sup>Bh|doi=10.1140/epja/i2004-10020-2|year=2004|last1=Gan |first1=Z. G. |journal=The European Physical Journal A|volume=20|last2=Guo|first2=J. S.|last3=Wu|first3=X. L.|last4=Qin|first4=Z.|last5=Fan|first5=H. M.|last6=Lei|first6=X.G.|last7=Liu|first7=H.Y. |last8=Guo|first8=B.|last9=Xu|first9=H.G.
|last10=Chen|first10=R. F.|last11=Dong|first11=C. F.|last12=Zhang|first12=F. M.|last13=Wang|first13=H. L.|last14=Xie|first14=C. Y.|last15=Feng|first15=Z. Q.|last16=Zhen|first16=Y.|last17=Song|first17=L. T.|last18=Luo|first18=P.|last19=Xu|first19=H. S.|last20=Zhou|first20=X. H.|last21=Jin|first21=G. M.|last22=Ren|first22=Zhongzhou|pages=385–387|issue=3|bibcode = 2004EPJA...20..385G |s2cid=120622108 |display-authors=8}}</ref>

The reaction between targets of [[Chemistry:Curium|curium]]-248 and accelerated nuclei of [[Chemistry:Sodium|sodium]]-23 was studied for the first time in 2008 by the team at RIKEN, Japan, in order to study the decay properties of <sup>266</sup>Bh, which is a decay product in their claimed decay chains of [[Chemistry:Nihonium|nihonium]]:<ref>{{cite journal |arxiv=0904.1093 |doi=10.1143/JPSJ.78.064201 |title=Decay Properties of <sup>266</sup>Bh and <sup>262</sup>Db Produced in the <sup>248</sup>Cm + <sup>23</sup>Na Reaction |year=2009 |last1=Morita |first1=Kosuke |journal=Journal of the Physical Society of Japan |volume=78 |pages=064201 |issue=6|bibcode = 2009JPSJ...78f4201M |last2=Morimoto |first2=Kouji |last3=Kaji |first3=Daiya |last4=Haba |first4=Hiromitsu |last5=Ozeki |first5=Kazutaka |last6=Kudou |first6=Yuki |last7=Sato |first7=Nozomi |last8=Sumita |first8=Takayuki |last9=Yoneda |first9=Akira |last10=Ichikawa |first10=Takatoshi |last11=Fujimori |first11=Yasuyuki |last12=Goto |first12=Sin-Ichi |last13=Ideguchi |first13=Eiji |last14=Kasamatsu |first14=Yoshitaka |last15=Katori |first15=Kenji |last16=Komori |first16=Yukiko |last17=Koura |first17=Hiroyuki |last18=Kudo |first18=Hisaaki |last19=Ooe |first19=Kazuhiro |last20=Ozawa |first20=Akira |last21=Tokanai |first21=Fuyuki |last22=Tsukada |first22=Kazuaki |last23=Yamaguchi |first23=Takayuki |last24=Yoshida |first24=Atsushi |s2cid=16415500 |display-authors=0}}</ref>

:{{nuclide|link=yes|curium|248}} + {{nuclide|link=yes|sodium|23}} → {{nuclide|bohrium|271−x}} + x {{SubatomicParticle|link=yes|neutron}} (x = 4 or 5)

The decay of <sup>266</sup>Bh by the emission of alpha particles with energies of 9.05–9.23&nbsp;MeV was further confirmed in 2010.<ref>{{cite journal|last1=Morita|first1=K.|last2=Morimoto|first2=K.|last3=Kaji|first3=D.|last4=Haba|first4=H.|last5=Ozeki|first5=K.|last6=Kudou|first6=Y.|last7=Sato|first7=N.|last8=Sumita|first8=T.|last9=Yoneda|first9=A. |last10=Ichikawa|first10=T.|last11=Fujimori|first11=Y.|last12=Goto|first12=S.|last13=Ideguchi|first13=E.|last14=Kasamatsu|first14=Y.|last15=Katori|first15=K.|last16=Komori|first16=Y.|last17=Koura|first17=H.|last18=Kudo|first18=H.|last19=Ooe|first19=K.|last20=Ozawa|first20=A.|last21=Tokanai|first21=F.|last22=Tsukada|first22=K.|last23=Yamaguchi|first23=T.|last24=Yoshida|first24=A.|last25=Susa|first25=Hajime|last26=Arnould|first26=Marcel|last27=Gales|first27=Sydney|last28=Motobayashi|first28=Tohru|last29=Scheidenberger|first29=Christoph|last30=Utsunomiya|first30=Hiroaki|title=Decay Properties of <sup>266</sup>Bh and <sup>262</sup>Db Produced in the <sup>248</sup>Cm+<sup>23</sup>Na Reaction—Further Confirmation of the [sup 278]113 Decay Chain—|pages=331|year=2010|doi=10.1063/1.3455961|series=AIP Conference Proceedings}}</ref>

The first attempts to synthesize bohrium by hot fusion pathways were performed in 1979 by the team at Dubna, using the reaction between accelerated nuclei of [[Chemistry:Neon|neon]]-22 and targets of [[Chemistry:Berkelium|berkelium]]-249:

:{{nuclide|link=yes|berkelium|249}} + {{nuclide|link=yes|neon|22}} → {{nuclide|bohrium|271−x}} + x {{SubatomicParticle|link=yes|neutron}} (x = 4 or 5)

The reaction was repeated in 1983. In both cases, they were unable to detect any [[Physics:Spontaneous fission|spontaneous fission]] from nuclei of bohrium. More recently, hot fusions pathways to bohrium have been re-investigated in order to allow for the synthesis of more long-lived, [[Physics:Neutron|neutron]] rich isotopes to allow a first chemical study of bohrium. In 1999, the team at LBNL claimed the discovery of long-lived <sup>267</sup>Bh (5 atoms) and <sup>266</sup>Bh (1 atom).<ref name="266Bh">{{cite journal|doi=10.1103/PhysRevLett.85.2697 |title=Evidence for New Isotopes of Element 107: <sup>266</sup>Bh and <sup>267</sup>Bh|year=2000|last1=Wilk |first1=P. A.|journal=Physical Review Letters|volume=85|pages=2697–700|pmid=10991211|last2=Gregorich|first2=KE|last3=Turler|first3=A|last4=Laue|first4=CA|last5=Eichler|first5=R|last6=Ninov V|first6=V|last7=Adams|first7=JL|last8=Kirbach|first8=UW|last9=Lane|first9=MR |last10=Lee|first10=D.|last11=Patin|first11=J.|last12=Shaughnessy|first12=D.|last13=Strellis|first13=D.|last14=Nitsche|first14=H.|last15=Hoffman|first15=D.|issue=13|bibcode=2000PhRvL..85.2697W|display-authors=8|url=https://zenodo.org/record/1233933}}</ref> Later, both of these were confirmed.<ref name="Doi_">{{cite book|last1=Münzenberg|first1=G.|last2=Gupta|first2=M.|title=Handbook of Nuclear Chemistry|pages=877–923|year=2011|doi=10.1007/978-1-4419-0720-2_19|chapter=Production and Identification of Transactinide Elements|isbn=978-1-4419-0719-6}}</ref> The team at the Paul Scherrer Institute (PSI) in [[Place:Bern|Bern]], Switzerland later synthesized 6 atoms of <sup>267</sup>Bh in the first definitive study of the chemistry of bohrium.<ref name="00Ei01">[http://www.gsi.de/informationen/wti/library/scientificreport2000/Chemistry/9/r_eichler_jb2000.pdf "Gas chemical investigation of bohrium (Bh, element 107)"] {{webarchive|url=https://web.archive.org/web/20080228023225/http://www.gsi.de/informationen/wti/library/scientificreport2000/Chemistry/9/r_eichler_jb2000.pdf |date=2008-02-28 }}, Eichler et al., ''GSI Annual Report 2000''. Retrieved on 2008-02-29</ref>

===As decay products===
<div style="float:right; margin:0; font-size:85%;">
{|class="wikitable" style="text-align:center"
|+List of bohrium isotopes observed by decay
! Evaporation residue !! Observed bohrium isotope
|-
|<sup>294</sup>Lv, <sup>290</sup>Fl, <sup>290</sup>Nh, <sup>286</sup>Rg, <sup>282</sup>Mt ?|| <sup>278</sup>Bh ?
|-
|<sup>294</sup>Ts, <sup>290</sup>Mc, <sup>286</sup>Nh, <sup>282</sup>Rg, <sup>278</sup>Mt||<sup>274</sup>Bh<ref name="274Bh" />
|-
|<sup>288</sup>Mc, <sup>284</sup>Nh, <sup>280</sup>Rg, <sup>276</sup>Mt||<sup>272</sup>Bh<ref name="270Bh">{{cite book|doi=10.1063/1.2746600|chapter=Heaviest Nuclei Produced in 48Ca-induced Reactions (Synthesis and Decay Properties)|title=AIP Conference Proceedings|year=2007|last1=Oganessian|first1=Yu. Ts.|last2=Penionzhkevich|first2=Yu. E.|last3=Cherepanov|first3=E. A.|volume=912|pages=235–246}}</ref><ref name="04Mo01">{{cite journal|title=Experiment on the Synthesis of Element 113 in the Reaction <sup>209</sup>Bi(<sup>70</sup>Zn,n)<sup>278</sup>113|year=2004|journal=Journal of the Physical Society of Japan|volume=73|issue=10|pages=2593–2596|doi=10.1143/JPSJ.73.2593|bibcode=2004JPSJ...73.2593M|last1=Morita|first1=Kosuke|last2=Morimoto|first2=Kouji|last3=Kaji|first3=Daiya|last4=Akiyama|first4=Takahiro|last5=Goto|first5=Sin-ichi|last6=Haba|first6=Hiromitsu|first7=Eiji |last7=Ideguchi|first8=Rituparna |last8=Kanungo|first9=Kenji |last9=Katori|first10=Hiroyuki |last10=Koura|first11=Hisaaki |last11=Kudo|first12=Tetsuya |last12=Ohnishi|first13=Akira |last13=Ozawa|first14=Toshimi |last14=Suda|first15=Keisuke |last15=Sueki|first16=HuShan |last16=Xu|first17=Takayuki |last17=Yamaguchi|first18=Akira |last18=Yoneda|first19=Atsushi |last19=Yoshida|first20=YuLiang |last20=Zhao|doi-access=}}</ref>
|-
|<sup>287</sup>Mc, <sup>283</sup>Nh, <sup>279</sup>Rg, <sup>275</sup>Mt||<sup>271</sup>Bh<ref name="270Bh" />
|-
|<sup>286</sup>Mc, <sup>282</sup>Nh, <sup>278</sup>Rg, <sup>274</sup>Mt||<sup>270</sup>Bh<ref name="270Bh" />
|-
|<sup>278</sup>Nh, <sup>274</sup>Rg, <sup>270</sup>Mt||<sup>266</sup>Bh<ref name="04Mo01" />
|-
|<sup>272</sup>Rg, <sup>268</sup>Mt||<sup>264</sup>Bh<ref name="264Bh">{{cite journal|doi=10.1007/BF01291182 |title=The new element 111 |year=1995 |last1=Hofmann |first1=S. |journal=Zeitschrift für Physik A |volume=350 |pages=281–282 |last2=Ninov |first2=V. |last3=Heßberger |first3=F. P. |last4=Armbruster |first4=P. |last5=Folger |first5=H. |last6=Münzenberg |first6=G. |last7=Schött |first7=H. J. |last8=Popeko |first8=A. G. |last9=Yeremin |first9=A. V. |first10=A. N. |last10=Andreyev |first11=S. |last11=Saro |first12=R. |last12=Janik |first13=M. |last13=Leino |bibcode=1995ZPhyA.350..281H |issue=4 |s2cid=18804192 |url=http://wwwsusi4.gsi.de/forschung/kp/kp2/ship/111publication.pdf |archive-url=https://web.archive.org/web/20140116120246/http://wwwsusi4.gsi.de/forschung/kp/kp2/ship/111publication.pdf |url-status=dead |archive-date=2014-01-16 }}</ref>
|-
|<sup>266</sup>Mt||<sup>262</sup>Bh<ref name="82Mu01">{{cite journal|title=Observation of one correlated α-decay in the reaction <sup>58</sup>Fe on <sup>209</sup>Bi→<sup>267</sup>109|doi=10.1007/BF01420157|year=1982|journal=Zeitschrift für Physik A|volume=309|issue=1|pages=89–90|last1=Münzenberg|first1=G.|last2=Armbruster|first2=P.|last3=Heßberger|first3=F. P.|last4=Hofmann|first4=S.|last5=Poppensieker|first5=K.|last6=Reisdorf|first6=W.|last7=Schneider|first7=J. H. R.|last8=Schneider|first8=W. F. W.|last9=Schmidt|first9=K.-H.|first10=C.-C.|last10=Sahm|first11=D.|last11=Vermeulen|bibcode = 1982ZPhyA.309...89M|s2cid=120062541 }}</ref>
|}
</div>
Bohrium has been detected in the decay chains of elements with a higher [[Physics:Atomic number|atomic number]], such as [[Chemistry:Meitnerium|meitnerium]]. Meitnerium currently has seven known isotopes; all of them undergo alpha decays to become bohrium nuclei, with mass numbers between 262 and 274. Parent meitnerium nuclei can be themselves decay products of [[Chemistry:Roentgenium|roentgenium]], [[Chemistry:Nihonium|nihonium]], [[Chemistry:Flerovium|flerovium]], [[Chemistry:Moscovium|moscovium]], [[Chemistry:Livermorium|livermorium]], or [[Chemistry:Tennessine|tennessine]].<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 |last=Sonzogni |first=Alejandro |location=National Nuclear Data Center |access-date=2008-06-06 |archive-date=2019-04-02 |archive-url=https://web.archive.org/web/20190402195353/https://www.nndc.bnl.gov/nudat2/ |url-status=dead }}</ref> For example, in January 2010, the Dubna team ([[Organization:Joint Institute for Nuclear Research|JINR]]) identified bohrium-274 as a product in the decay of tennessine via an alpha decay sequence:<ref name="274Bh" />

:{{nuclide|tennessine|294}} → {{nuclide|moscovium|290}} + {{nuclide|helium|4}}
:{{nuclide|moscovium|290}} → {{nuclide|nihonium|286}} + {{nuclide|helium|4}}
:{{nuclide|nihonium|286}} → {{nuclide|roentgenium|282}} + {{nuclide|helium|4}}
:{{nuclide|roentgenium|282}} → {{nuclide|meitnerium|278}} + {{nuclide|helium|4}}
:{{nuclide|meitnerium|278}} → {{nuclide|bohrium|274}} + {{nuclide|helium|4}}

==Nuclear isomerism==
;<sup>262</sup>Bh
The only confirmed example of isomerism in bohrium is in the isotope <sup>262</sup>Bh. Direct synthesis of <sup>262</sup>Bh results in two states, a [[Physics:Ground state|ground state]] and an [[Physics:Nuclear isomer|isomeric state]]. The ground state is confirmed to decay by alpha decay, emitting alpha particles with energies of 10.08, 9.82, and 9.76&nbsp;MeV, and has a revised half-life of 84&nbsp;ms. The excited state also decays by alpha decay, emitting alpha particles with energies of 10.37 and 10.24&nbsp;MeV, and has a revised half-life of 9.6 ms.<ref name="262Bh" />

==Chemical yields of isotopes==

===Cold fusion===
The table below provides cross-sections and excitation energies for cold fusion reactions producing bohrium isotopes directly. Data in bold represents maxima derived from excitation function measurements. + represents an observed exit channel.

{| class="wikitable"
|-
! Projectile
! Target
! CN
! 1n 
! 2n
! 3n
|-
| <sup>55</sup>Mn
| <sup>208</sup>Pb
| <sup>263</sup>Bh
| '''590&nbsp;pb, 14.1&nbsp;MeV'''
| '''~35&nbsp;pb'''
|
|-
| <sup>54</sup>Cr
| <sup>209</sup>Bi
| <sup>263</sup>Bh
| '''510&nbsp;pb, 15.8&nbsp;MeV'''
| '''~50&nbsp;pb'''
|
|-
| <sup>52</sup>Cr
| <sup>209</sup>Bi
| <sup>261</sup>Bh
| 59&nbsp;pb, 15.0&nbsp;MeV
| 
|
|}

===Hot fusion===
The table below provides cross-sections and excitation energies for hot fusion reactions producing bohrium isotopes directly. Data in bold represents maxima derived from excitation function measurements. + represents an observed exit channel.

{| class="wikitable"
|-
! Projectile
! Target
! CN
! 3n
! 4n
! 5n
|-
| <sup>26</sup>Mg
| <sup>243</sup>Am
| <sup>271</sup>Bh
| +
| +
| +
|-
| <sup>22</sup>Ne
| <sup>249</sup>Bk
| <sup>271</sup>Bh
| 
| ~96&nbsp;pb
| +
|}

==References==
{{Reflist}}
* Isotope masses from:
**{{cite journal |author=M. Wang |author2=G. Audi |author3=A. H. Wapstra |author4=F. G. Kondev |author5=M. MacCormick |author6=X. Xu|year=2012 |title=The AME2012 atomic mass evaluation (II). Tables, graphs and references. |url=http://amdc.in2p3.fr/masstables/Ame2012/Ame2012b-v2.pdf |journal=Chinese Physics C |volume=36 |issue= 12 |pages=1603–2014 |doi=10.1088/1674-1137/36/12/003|bibcode = 2012ChPhC..36....3M |hdl=11858/00-001M-0000-0010-23E8-5 |s2cid=250839471 |display-authors=0}}
**{{NUBASE 2003}}
* Isotopic compositions and standard atomic masses from:
**{{CIAAW 2005}}
* Half-life, spin, and isomer data selected from the following sources.
**{{NUBASE 2012}}
**{{NUBASE 2003}}
**{{NNDC}}
**{{CRC85|chapter=11}}
**{{cite web |author=Утенков В. К. (V. K. Utyonkov) |year=2008 |title=Синтез новых элементов 113-118 в реакциях полного слияния <sup>48</sup>Ca+<sup>238</sup>U-<sup>249</sup>Cf |language=ru, en |url=http://nuclphys.sinp.msu.ru/nseminar/12.02.08.pdf |publisher=JINR, Dubna |access-date=21 August 2012}}
**{{cite web |last=Oganessian |first=Yuri |year=2012 |title=Synthesis of SH-nuclei |url=http://www.ensarfp7.eu/what-is-ensar/projects/ecos/workshops-meetings/fushe2012/summaries-and-talks-1/FUSHE2012_Oganessian.pdf |access-date=3 September 2012}}
{{Navbox element isotopes}}

[[Category:Isotopes of bohrium| ]]
[[Category:Lists of isotopes by element|Bohrium]]

{{Sourceattribution|Isotopes of bohrium}}