Isotopes of roentgenium#Roentgenium-275

{{Anchor|Roentgenium-273|Roentgenium-275|Roentgenium-276|Roentgenium-277|Roentgenium-284|Roentgenium-285}}

{{Isotopes table

|symbol=Rg

|refs=NUBASE2020

|notes=unc(), mass#, EC, SF, spin#

}}

|-id=Roentgenium-272

| ²⁷²Rg

| 111

| 161

| 272.15327(25)#

| {{val|3.8|1.4|0.8|u=ms}}
[{{val|4.2|(11)|u=ms}}]

| α

| ²⁶⁸Mt

| 5+#, 6+#

|-id=Roentgenium-274

| ²⁷⁴RgNot directly synthesized, occurs as a decay product of ²⁷⁸Nh

| 111

| 163

| 274.15525(23)#

| {{val|12|17|5|u=ms}}
[{{val|20|(11)|u=ms}}]

| α

| ²⁷⁰Mt

|

|-id=Roentgenium-278

| ²⁷⁸RgNot directly synthesized, occurs as a decay product of ²⁸²Nh

| 111

| 167

| 278.16159(42)#

| {{val|4.6|5.5|1.6|u=ms}}{{Cite journal |title=New isotope ²⁸⁶Mc produced in the ²⁴³Am+⁴⁸Ca 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 |url=https://www.osti.gov/biblio/1905386 }}

| α

| ²⁷⁴Mt

|

|-id=Roentgenium-279

| rowspan=2|²⁷⁹RgNot directly synthesized, occurs in decay chain of ²⁸⁷Mc

| rowspan=2|111

| rowspan=2|168

| rowspan=2|279.16288(45)#

| rowspan=2|{{val|90|60|25|u=ms}}

| α (87%)

| ²⁷⁵Mt

|

|-

| SF (13%)

| (various)

|-id=Roentgenium-280

| rowspan=2|²⁸⁰RgNot directly synthesized, occurs in decay chain of ²⁸⁸Mc

| rowspan=2|111

| rowspan=2|169

| rowspan=2|280.16520(57)#

| rowspan=2|{{val|3.9|(3)|u=s}}

| α (87%)

| ²⁷⁶Mt

|

|-

| EC (13%){{Cite journal |arxiv = 1502.03030|doi = 10.1016/j.nuclphysa.2016.04.025|title = Recoil-α-fission and recoil-α–α-fission events observed in the reaction 48Ca + 243Am|journal = Nuclear Physics A|volume = 953|pages = 117–138|year = 2016|last1 = Forsberg|first1 = U.|last2 = Rudolph|first2 = D.|last3 = Andersson|first3 = L.-L.|last4 = Di Nitto|first4 = A.|last5 = Düllmann|first5 = Ch.E.|last6 = Fahlander|first6 = C.|last7 = Gates|first7 = J.M.|last8 = Golubev|first8 = P.|last9 = Gregorich|first9 = K.E.|last10 = Gross|first10 = C.J.|last11 = Herzberg|first11 = R.-D.|last12 = Heßberger|first12 = F.P.|last13 = Khuyagbaatar|first13 = J.|last14 = Kratz|first14 = J.V.|last15 = Rykaczewski|first15 = K.|last16 = Sarmiento|first16 = L.G.|last17 = Schädel|first17 = M.|last18 = Yakushev|first18 = A.|last19 = Åberg|first19 = S.|last20 = Ackermann|first20 = D.|last21 = Block|first21 = M.|last22 = Brand|first22 = H.|last23 = Carlsson|first23 = B.G.|last24 = Cox|first24 = D.|last25 = Derkx|first25 = X.|last26 = Dobaczewski|first26 = J.|last27 = Eberhardt|first27 = K.|last28 = Even|first28 = J.|last29 = Gerl|first29 = J.|last30 = Jäger|first30 = E.|display-authors = 29|bibcode = 2016NuPhA.953..117F|s2cid = 55598355}}

| ²⁸⁰Ds

|

|-id=Roentgenium-281

|rowspan=2 |²⁸¹RgNot directly synthesized, occurs in decay chain of ²⁹³Ts

|rowspan=2 |111

|rowspan=2 |170

|rowspan=2 |281.16676(83)#

|rowspan=2 |{{val|11|3|1|u=s}}

| SF (86%)

| (various)

|rowspan=2|

|-

| α (14%)

| ²⁷⁷Mt

|-id=Roentgenium-282

| ²⁸²RgNot directly synthesized, occurs in decay chain of ²⁹⁴Ts

| 111

| 171

| 282.16934(63)#

| {{val|100|70|30|u=s}}
[{{val|130|(50)|u=s}}]

| α

| ²⁷⁸Mt

|

|-id=Roentgenium-283

| ²⁸³RgNot directly synthesized, occurs in decay chain of ²⁸⁷Fl; unconfirmed

| 111

| 172

| 283.17110(73)#

| 5.1 min?

| SF

| (various)

|

|-id=Roentgenium-286

| ²⁸⁶RgNot directly synthesised, occurs in decay chain of ²⁹⁰Fl and ²⁹⁴Lv; unconfirmed

| 111

| 175

| 286.17876(49)#

| 10.7 min?

| α

| ²⁸²Mt

|

{{Isotopes table/footer}}

Super-heavy elements such as roentgenium are produced by bombarding lighter elements in particle accelerators that induce fusion reactions. Whereas the lightest isotope of roentgenium, roentgenium-272, can be synthesized directly this way, all the heavier roentgenium isotopes have only been observed as decay products of elements with higher atomic numbers.{{Cite journal |first1=Peter |last1=Armbruster |name-list-style=amp |first2=Gottfried |last2=Munzenberg |title=Creating superheavy elements |journal=Scientific American |volume=34 |pages=36–42 |year=1989}}

Depending on the energies involved, fusion reactions can be categorized as "hot" or "cold". In hot fusion reactions, very light, high-energy projectiles are accelerated toward very heavy targets (actinides), giving rise to compound nuclei at high excitation energy (~40–50 MeV) that may either fission or evaporate several (3 to 5) neutrons.{{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 |url=https://www.dora.lib4ri.ch/psi/islandora/object/psi%3A16806/datastream/PDF/Barber-2009-Discovery_of_the_element_with-%28published_version%29.pdf }} In cold fusion reactions, the produced fused nuclei have a relatively low excitation energy (~10–20 MeV), which decreases the probability that these products will undergo fission reactions. As the fused nuclei cool to the ground state, they require emission of only one or two neutrons, and thus, allows for the generation of more neutron-rich products. The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion).{{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 }}

The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z=111.

class="wikitable" style="text-align:center" ! Target !! Projectile !! CN !! Attempt result
205Tl |70Zn||275Rg||{{No|Failure to date}}
208Pb |65Cu||273Rg||{{Yes|Successful reaction}}
209Bi |64Ni||273Rg||{{Yes|Successful reaction}}
231Pa |48Ca||279Rg||{{unk|Reaction yet to be attempted}}
238U |41K||279Rg||{{unk|Reaction yet to be attempted}}
244Pu |37Cl||281Rg||{{unk|Reaction yet to be attempted}}
248Cm |31P||279Rg||{{unk|Reaction yet to be attempted}}
250Cm |31P||281Rg||{{unk|Reaction yet to be attempted}}

Before the first successful synthesis of roentgenium in 1994 by the GSI team, a team at the Joint Institute for Nuclear Research in Dubna, Russia, also tried to synthesize roentgenium by bombarding bismuth-209 with nickel-64 in 1986. No roentgenium atoms were identified. After an upgrade of their facilities, the team at GSI successfully detected 3 atoms of ²⁷²Rg in their discovery experiment.{{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. |last10=Andreyev |first10=A. N. |last11=Saro |first11=S. |last12=Janik |first12=R. |last13=Leino |first13=M. |bibcode = 1995ZPhyA.350..281H |issue=4 |s2cid=18804192 |display-authors=8}} A further 3 atoms were synthesized in 2002.{{Cite journal |doi=10.1140/epja/i2001-10119-x |title=New results on elements 111 and 112 |year=2002 |last1=Hofmann |first1=S. |journal=The European Physical Journal A |volume=14 |pages=147–157 |last2=Heßberger |first2=F. P. |last3=Ackermann |first3=D. |last4=Münzenberg |first4=G. |last5=Antalic |first5=S. |last6=Cagarda |first6=P. |last7=Kindler |first7=B. |last8=Kojouharova |first8=J. |last9=Leino |first9=M. |last10=Lommel |first10=B. |last11=Mann |first11=R. |last12=Popeko |first12=A.G. |last13=Reshitko |first13=S. |last14=Śaro |first14=S. |last15=Uusitalo |first15=J. |last16=Yeremin |first16=A.V. |issue=2 |display-authors=8|bibcode=2002EPJA...14..147H |s2cid=8773326 }} The discovery of roentgenium was confirmed in 2003 when a team at RIKEN measured the decays of 14 atoms of ²⁷²Rg.{{cite journal |last1=Morita |first1=K. |last2=Morimoto |first2=K. K. |last3=Kaji |first3=D. |last4=Goto |first4=S. |last5=Haba |first5=H. |last6=Ideguchi |first6=E. |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=Peter |first13=J. C. |last14=Suda |first14=T. |last15=Sueki |first15=K. |last16=Tanihata |first16=I. |last17=Tokanai |first17=F. |last18=Xu |first18=H. |last19=Yeremin |first19=A. V. |last20=Yoneda |first20=A. |last21=Yoshida |first21=A. |last22=Zhao |first22=Y.-L. |last23=Zheng |first23=T. |title=Status of heavy element research using GARIS at RIKEN |year=2004 |journal=Nuclear Physics A |volume=734 |pages=101–108 |doi=10.1016/j.nuclphysa.2004.01.019|bibcode=2004NuPhA.734..101M }}

The same roentgenium isotope was also observed by an American team at the Lawrence Berkeley National Laboratory (LBNL) from the reaction:

:{{nuclide|lead|208}} + {{nuclide|copper|65}} → {{nuclide|roentgenium|272}} + {{SubatomicParticle|neutron}}

This reaction was conducted as part of their study of projectiles with odd atomic number in cold fusion reactions.{{Cite journal |doi=10.1103/PhysRevLett.93.212702 |title=Development of an Odd-Z-Projectile Reaction for Heavy Element Synthesis: ²⁰⁸Pb(⁶⁴Ni,n)²⁷¹Ds and ²⁰⁸Pb(⁶⁵Cu,n)²⁷²111 |year=2004 |author=Folden, C. M. |journal=Physical Review Letters |volume=93 |pages=212702 |pmid=15601003 |issue=21 |bibcode=2004PhRvL..93u2702F |last2=Gregorich |first2=K. |last3=Düllmann|first3=Ch.|last4=Mahmud|first4=H.|last5=Pang|first5=G.|last6=Schwantes|first6=J.|last7=Sudowe|first7=R.|last8=Zielinski|first8=P.|last9=Nitsche|first9=H.|last10=Hoffman|first10=D.|url=https://digital.library.unt.edu/ark:/67531/metadc780605/m2/1/high_res_d/836679.pdf|display-authors=8}}

The ²⁰⁵Tl(⁷⁰Zn,n)²⁷⁴Rg reaction was tried by the RIKEN team in 2004 and repeated in 2010 in an attempt to secure the discovery of its parent ²⁷⁸Nh:{{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 |website=www.physics.adelaide.edu.au |publisher=26th International Nuclear Physics Conference |access-date=14 May 2017}}

:{{nuclide|thallium|205}} + {{nuclide|zinc|70}} → {{nuclide|roentgenium|274}} + {{SubatomicParticle|neutron}}

Due to the weakness of the thallium target, they were unable to detect any atoms of ²⁷⁴Rg.

All the isotopes of roentgenium except roentgenium-272 have been detected only in the decay chains of elements with a higher atomic number, such as nihonium. Nihonium currently has six known isotopes, with two more unconfirmed; all of them undergo alpha decays to become roentgenium nuclei, with mass numbers between 274 and 286. Parent nihonium nuclei can be themselves decay products of moscovium and tennessine, and (via unconfirmed branches) flerovium and livermorium.{{cite web |url=http://www.nndc.bnl.gov/chart/reCenter.jsp?z=111&n=170 |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=2012-12-11 |archive-url=https://archive.today/20121211232515/http://www.nndc.bnl.gov/chart/reCenter.jsp?z=111&n=170 |url-status=dead }} For example, in January 2010, the Dubna team (JINR) identified roentgenium-281 as a final product in the decay of tennessine via an alpha decay sequence:

:{{nuclide|tennessine|293}} → {{nuclide|moscovium|289}} + {{nuclide|helium|4}}

:{{nuclide|moscovium|289}} → {{nuclide|nihonium|285}} + {{nuclide|helium|4}}

:{{nuclide|nihonium|285}} → {{nuclide|roentgenium|281}} + {{nuclide|helium|4}}

;²⁷⁴Rg

Two atoms of ²⁷⁴Rg have been observed in the decay chain of ²⁷⁸Nh. They decay by alpha emission, emitting alpha particles with different energies, and have different lifetimes. In addition, the two entire decay chains appear to be different. This suggests the presence of two nuclear isomers but further research is required.{{Failed verification|date=September 2024}}

;²⁷²Rg

Four alpha particles emitted from ²⁷²Rg with energies of 11.37, 11.03, 10.82, and 10.40 MeV have been detected. The GSI measured ²⁷²Rg to have a half-life of 1.6 ms while recent data from RIKEN have given a half-life of 3.8 ms. The conflicting data may be due to nuclear isomers but the current data are insufficient to come to any firm assignments.

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

class="wikitable" style="text-align:center"
Projectile	Target	CN	1n	2n	3n
64Ni	209Bi	273Rg	3.5 pb, 12.5 MeV
65Cu	208Pb	273Rg	1.7 pb, 13.2 MeV

The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.

DNS = Di-nuclear system; σ = cross section

class="wikitable" style="text-align:center"
Target	Projectile	CN	Channel (product)	σmax	Model	Ref
238U |41K||279Rg||4n (275Rg)||0.21 pb||DNS||{{cite journal|last1=Feng|first1=Z.|last2=Jin|first2=G.|last3=Li|first3=J.|title=Production of new superheavy Z=108–114 nuclei with 238U, 244Pu and 248,250Cm targets|date=2009|arxiv=0912.4069|journal=Physical Review C|volume=80|issue=5|pages=057601|doi=10.1103/PhysRevC.80.057601|s2cid=118733755 }}
244Pu |37Cl||281Rg||4n (277Rg)||0.33 pb||DNS||
248Cm |31P||279Rg||4n (275Rg)||1.85 pb||DNS||
250Cm |31P||281Rg||4n (277Rg)||0.41 pb||DNS||

{{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=etal}}
• {{NUBASE 2003}}
• Half-life, spin, and isomer data selected from the following sources.
• {{NUBASE 2003}}
• {{NNDC}}
• {{CRC85|chapter=11}}
• {{cite journal|author=Yu. Ts. Oganessian |title=Heaviest nuclei from ⁴⁸Ca-induced reactions |journal=Journal of Physics G |year=2007 |volume=34 |issue=4 |pages=R165–R242|bibcode = 2007JPhG...34R.165O |doi = 10.1088/0954-3899/34/4/R01 }}

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Category:Roentgenium

Roentgenium