Editing Nihonium (section)

==== 2009–2015 ====
The JWP published its report on elements 113–116 and 118 in 2011. It recognised the JINR–LLNL collaboration as having discovered elements 114 and 116, but did not accept either team's claim to element 113 and did not accept the JINR–LLNL claims to elements 115 and 118. The JINR–LLNL claim to elements 115 and 113 had been founded on chemical identification of their daughter dubnium, but the JWP objected that current theory could not distinguish between superheavy [[group 4 element|group 4]] and group 5 elements by their chemical properties with enough confidence to allow this assignment.<ref name="JWP">{{cite journal |author=Barber, Robert C. |author2=Karol, Paul J |author3=Nakahara, Hiromichi |author4=Vardaci, Emanuele |author5=Vogt, Erich W. |title=Discovery of the elements with atomic numbers greater than or equal to 113 (IUPAC Technical Report) |doi=10.1351/PAC-REP-10-05-01 |journal=Pure Appl. Chem. |date=2011 |volume=83 |issue=7 |page=1485|doi-access=free }}</ref> The decay properties of all the nuclei in the decay chain of element 115 had not been previously characterised before the JINR experiments, a situation which the JWP generally considers "troublesome, but not necessarily exclusive", and with the small number of atoms produced with neither known daughters nor cross-reactions the JWP considered that their criteria had not been fulfilled.<ref name="JWP" /> The JWP did not accept the Riken team's claim either due to inconsistencies in the decay data, the small number of atoms of element 113 produced, and the lack of unambiguous anchors to known isotopes.<ref name="JWP" />

In early 2009, the Riken team synthesised the decay product <sup>266</sup>Bh directly in the <sup>248</sup>Cm + <sup>23</sup>Na reaction to establish its link with <sup>278</sup>113 as a cross-bombardment. They also established the branched decay of <sup>262</sup>Db, which sometimes underwent spontaneous fission and sometimes underwent the previously known alpha decay to <sup>258</sup>Lr.<ref>{{cite journal |last1=Morita |first1=Kosuke |last2=Morimoto |first2=Kouji |first3=Daiya |last3=Kaji |first4=Hiromitsu |last4=Haba |first5=Kazutaka |last5=Ozeki |first6=Yuki |last6=Kudou |first7=Nozomi |last7=Sato |first8=Takayuki |last8=Sumita |first9=Akira |last9=Yoneda |first10=Takatoshi |last10=Ichikawa |first11=Yasuyuki |last11=Fujimori |first12=Sin-ichi |last12=Goto |first13=Eiji |last13=Ideguchi |first14=Yoshitaka |last14=Kasamatsu |first15=Kenji |last15=Katori |first16=Yukiko |last16=Komori |first17=Hiroyuki |last17=Koura |first18=Hisaaki |last18=Kudo |first19=Kazuhiro |last19=Ooe |first20=Akira |last20=Ozawa |first21=Fuyuki |last21=Tokanai |first22=Kazuaki |last22=Tsukada |first23=Takayuki |last23=Yamaguchi |first24=Atsushi |last24=Yoshida |date=25 May 2009 |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 |journal=Journal of the Physical Society of Japan |volume=78 |issue=6 |pages=064201–1–6 |doi=10.1143/JPSJ.78.064201 |arxiv=0904.1093 |bibcode=2009JPSJ...78f4201M|s2cid=16415500 }}</ref><ref name="morimoto">{{cite web |url=http://www.kernchemie.uni-mainz.de/downloads/che_7/presentations/morimoto.pdf |title=Production and Decay Properties of <sup>266</sup>Bh and its daughter nuclei by using the <sup>248</sup>Cm(<sup>23</sup>Na,5n)<sup>266</sup>Bh Reaction |last1=Morimoto |first1=Kouji |first2=K. |last2=Morita |first3=D. |last3=Kaji |first4=H. |last4=Haba |first5=K. |last5=Ozeki |first6=Y. |last6=Kudou |first7=N. |last7=Sato |first8=T. |last8=Sumita |first9=A. |last9=Yoneda |first10=T. |last10=Ichikawa |first11=Y. |last11=Fujimori |first12=S. |last12=Goto |first13=E. |last13=Ideguchi |first14=Y. |last14=Kasamatsu |first15=K. |last15=Katori |first16=Y. |last16=Komori |first17=H. |last17=Koura |first18=H. |last18=Kudo |first19=K. |last19=Ooe |first20=A. |last20=Ozawa |first21=F. |last21=Tokanai |first22=K. |last22=Tsukada |first23=T. |last23=Yamaguchi |first24=A. |last24=Yoshida |date=October 2009 |via=[[University of Mainz]] |access-date=28 April 2017 |archive-url=https://web.archive.org/web/20170921193318/http://www.kernchemie.uni-mainz.de/downloads/che_7/presentations/morimoto.pdf |archive-date=21 September 2017 |url-status=dead}}</ref>

In late 2009, the JINR–LLNL collaboration studied the <sup>249</sup>Bk + <sup>48</sup>Ca reaction in an effort to produce [[tennessine|element 117]], which would decay to elements 115 and 113 and bolster their claims in a cross-reaction. They were now joined by scientists from [[Oak Ridge National Laboratory]] (ORNL) and [[Vanderbilt University]], both in [[Tennessee]], United States,<ref name="Chapman" /> who helped procure the rare and highly radioactive [[berkelium]] target necessary to complete the JINR's calcium-48 campaign to synthesise the heaviest elements on the periodic table.<ref name="Chapman" /> Two isotopes of element 117 were synthesised, decaying to element 115 and then element 113:<ref name="e117">{{cite journal |last1=Oganessian |first1=Yuri Ts. |last2=Abdullin |first2=F. Sh. |last3=Bailey |first3=P. D. |last4=Benker |first4=D. E. |last5=Bennett |first5=M. E. |last6=Dmitriev |first6=S. N. |last7=Ezold |first7=J. G. |last8=Hamilton |first8=J. H. |last9=Henderson |first9=R. A. | first10=M. G. |last10=Itkis |first11=Yuri V. |last11=Lobanov |first12=A. N. |last12=Mezentsev |first13=K. J. |last13=Moody |first14=S. L. |last14=Nelson |first15=A. N. |last15=Polyakov |first16=C. E. |last16=Porter |first17=A. V. |last17=Ramayya |first18=F. D. |last18=Riley |first19=J. B. |last19=Roberto | first20=M. A. |last20=Ryabinin |first21=K. P. |last21=Rykaczewski |first22=R. N. |last22=Sagaidak |first23=D. A. |last23=Shaughnessy |first24=I. V. |last24=Shirokovsky |first25=M. A. |last25=Stoyer |first26=V. G. |last26=Subbotin |first27=R. |last27=Sudowe |first28=A. M. |last28=Sukhov |first29=Yu. S. |last29=Tsyganov | first30=Vladimir K. |last30=Utyonkov |first31=A. A. |last31=Voinov |first32=G. K. |last32=Vostokin |first33=P. A. |last33=Wilk |title=Synthesis of a New Element with Atomic Number ''Z''=117 |date=9 April 2010 |journal=Physical Review Letters |volume=104 |issue=14 |pages=142502 |doi=10.1103/PhysRevLett.104.142502 |pmid=20481935 |bibcode=2010PhRvL.104n2502O |url=https://www.researchgate.net/publication/44610795|doi-access=free }}</ref>

:{{nuclide|link=no|Berkelium|249}} + {{nuclide|link=no|Calcium|48}} → <sup>297</sup>117* → <sup>294</sup>117 + 3 {{SubatomicParticle|link=no|neutron}} → <sup>290</sup>115 + α → <sup>286</sup>113 + α
:{{nuclide|link=no|Berkelium|249}} + {{nuclide|link=no|Calcium|48}} → <sup>297</sup>117* → <sup>293</sup>117 + 4 {{SubatomicParticle|link=no|neutron}} → <sup>289</sup>115 + α → <sup>285</sup>113 + α

The new isotopes <sup>285</sup>113 and <sup>286</sup>113 produced did not overlap with the previously claimed <sup>282</sup>113, <sup>283</sup>113, and <sup>284</sup>113, so this reaction could not be used as a cross-bombardment to confirm the 2003 or 2006 claims.<ref name="Karol" />

In March 2010, the Riken team again attempted to synthesise <sup>274</sup>Rg directly through the <sup>205</sup>Tl + <sup>70</sup>Zn reaction with upgraded equipment; they failed again and abandoned this cross-bombardment route.<ref name="Morimoto2016">{{cite web |url=http://www.physics.adelaide.edu.au/cssm/workshops/inpc2016/talks/Morimoto_Mon_HallL_0930.pdf |title=The discovery of element 113 at RIKEN |last=Morimoto |first=Kouji |date=2016 |publisher=26th International Nuclear Physics Conference |access-date=14 May 2017}}</ref>

After 450 more days of irradiation of bismuth with zinc projectiles, Riken produced and identified another <sup>278</sup>113 atom in August 2012<!--the 12th-->.<ref name="six-alpha">{{cite journal |journal=Journal of the Physical Society of Japan |volume=81 |pages=103201 |date=2012 |title=New Results in the Production and Decay of an Isotope, <sup>278</sup>113, of the 113th Element |author=K. Morita |doi=10.1143/JPSJ.81.103201 |last2=Morimoto |first2=Kouji |last3=Kaji |first3=Daiya |last4=Haba |first4=Hiromitsu |last5=Ozeki |first5=Kazutaka |last6=Kudou |first6=Yuki |last7=Sumita |first7=Takayuki |last8=Wakabayashi |first8=Yasuo |last9=Yoneda |first9=Akira|first10=Kengo |last10=Tanaka |first11=Sayaka |last11=Yamaki |first12=Ryutaro |last12=Sakai |first13=Takahiro |last13=Akiyama |first14=Shin-ichi |last14=Goto |first15=Hiroo |last15=Hasebe |first16=Minghui |last16=Huang |first17=Tianheng |last17=Huang |first18=Eiji |last18=Ideguchi |first19=Yoshitaka |last19=Kasamatsu|first20=Kenji |last20=Katori |first21=Yoshiki |last21=Kariya |first22=Hidetoshi |last22=Kikunaga |first23=Hiroyuki |last23=Koura |first24=Hisaaki |last24=Kudo |first25=Akihiro |last25=Mashiko |first26=Keita |last26=Mayama |first27=Shin-ichi |last27=Mitsuoka |first28=Toru |last28=Moriya |first29=Masashi |last29=Murakami|first30=Hirohumi |last30=Murayama |first31=Saori |last31=Namai |first32=Akira |last32=Ozawa |first33=Nozomi |last33=Sato |first34=Keisuke |last34=Sueki |first35=Mirei |last35=Takeyama |first36=Fuyuki |last36=Tokanai |first37=Takayuki |last37=Yamaguchi |first38=Atsushi |last38=Yoshida |issue=10|display-authors=10 |arxiv=1209.6431 |bibcode=2012JPSJ...81j3201M|s2cid=119217928 }}</ref> Although electricity prices had soared since the [[2011 Tōhoku earthquake and tsunami]], and Riken had ordered the shutdown of the accelerator programs to save money, Morita's team was permitted to continue with one experiment, and they chose their attempt to confirm their synthesis of element 113.<ref name="podcast">{{cite web |url=https://www.chemistryworld.com/podcasts/nihonium/3008633.article |title=Nihonium |last=Chapman |first=Kit |date=8 February 2018 |website=Chemistry World |publisher=[[Royal Society of Chemistry]] |access-date=20 March 2018}}</ref> In this case, a series of six alpha decays was observed, leading to an isotope of [[mendelevium]]:

:<sup>278</sup>113 → {{nuclide|link=no|Roentgenium|274}} + {{SubatomicParticle|link=no|alpha}} → {{nuclide|link=no|Meitnerium|270}} + {{SubatomicParticle|link=no|alpha}} → {{nuclide|link=no|Bohrium|266}} + {{SubatomicParticle|link=no|alpha}} → {{nuclide|link=no|Dubnium|262}} + {{SubatomicParticle|link=no|alpha}} → {{nuclide|link=no|Lawrencium|258}} + {{SubatomicParticle|link=no|alpha}} → {{nuclide|link=no|Mendelevium|254}} + {{SubatomicParticle|link=no|alpha}}

This decay chain differed from the previous observations at Riken mainly in the decay mode of <sup>262</sup>Db, which was previously observed to undergo spontaneous fission, but in this case instead alpha decayed; the alpha decay of <sup>262</sup>Db to <sup>258</sup>Lr is [[isotopes of dubnium|well-known]]. The team calculated the probability of accidental [[mathematical coincidence|coincidence]] to be 10<sup>−28</sup>, or totally negligible.<ref name="six-alpha" /> The resulting <sup>254</sup>Md atom then underwent [[electron capture]] to <sup>254</sup>[[fermium|Fm]], which underwent the seventh alpha decay in the chain to the long-lived <sup>250</sup>[[californium|Cf]], which has a half-life of around thirteen years.<ref>{{cite web |url=http://cyclotron.tamu.edu/she2015/assets/pdfs/presentations/Morita_SHE_2015_TAMU.pdf |title=SHE Research at RIKEN/GARIS |first=Kosuke |last=Morita |date=2015 |access-date=4 September 2018 |via=Texas A&M University Cyclotron Institute}}</ref>

The <sup>249</sup>Bk + <sup>48</sup>Ca experiment was repeated at the JINR in 2012 and 2013 with consistent results, and again at the GSI in 2014.<ref name="Karol" /> In August 2013, a team of researchers at [[Lund University]] in [[Lund]], Sweden, and at the GSI announced that they had repeated the 2003 <sup>243</sup>Am + <sup>48</sup>Ca experiment, confirming the findings of the JINR–LLNL collaboration.<ref name="RudolphForsberg2013" /><ref>{{cite news |url=http://www.lunduniversity.lu.se/article/existence-of-new-element-confirmed |agency=Lund University |title=Existence of new element confirmed |date=27 August 2013 |access-date=10 April 2016}}</ref> The same year, the 2003 experiment had been repeated at the JINR, now also creating the isotope <sup>289</sup>115 that could serve as a cross-bombardment for confirming their discovery of the [[tennessine|element 117]] isotope <sup>293</sup>117, as well as its daughter <sup>285</sup>113 as part of its decay chain.<ref name="Karol" /> Confirmation of <sup>288</sup>115 and its daughters was published by the team at the LBNL in August 2015.<ref>{{cite journal |doi=10.1103/PhysRevC.92.021301 |title=Decay spectroscopy of element 115 daughters: <sup>280</sup>Rg→<sup>276</sup>Mt and <sup>276</sup>Mt→Bh |journal=Physical Review C |volume=92 |issue=2 |pages=021301 |bibcode=2015PhRvC..92b1301G |year=2015 |last1=Gates |first1=J. M. |last2=Gregorich |first2=K. E. |last3=Gothe |first3=O. .R |last4=Uribe |first4=E. C. |last5=Pang |first5=G. K. |last6=Bleuel |first6=D. L. |last7=Block |first7=M. |last8=Clark |first8=R. M. |last9=Campbell |first9=C. M.|last10=Crawford|first10=H. L. |last11=Cromaz |first11=M. |last12=Di Nitto |first12=A. |last13=Düllmann |first13=Ch. E. |last14=Esker |first14=N. E. |last15=Fahlander |first15=C. |last16=Fallon |first16=P. |last17=Farjadi |first17=R. M. |last18=Forsberg |first18=U. |last19=Khuyagbaatar |first19=J.|last20=Loveland|first20=W. |last21=MacChiavelli |first21=A. O. |last22=May |first22=E. M. |last23=Mudder |first23=P. R. |last24=Olive |first24=D. T. |last25=Rice |first25=A. C. |last26=Rissanen |first26=J. |last27=Rudolph |first27=D. |last28=Sarmiento |first28=L. G. |last29=Shusterman |first29=J. A.|last30=Stoyer|first30=M. A.|display-authors=29|doi-access=free }}</ref>