Isotopes of roentgenium
Roentgenium (Rg) is a synthetic element, and thus a standard atomic mass cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 272Rg in 1994, which is also the only directly synthesized isotope, all others are decay products of nihonium, moscovium, and tennessine. There are 7 known radioisotopes from 272Rg to 282Rg. The longest-lived isotope is 282Rg with a half-life of 2.1 minutes.
Table
nuclide symbol |
Z(p) | N(n) | isotopic mass (u) |
half-life | decay mode(s)[n 1] |
daughter isotope(s) |
nuclear spin |
---|---|---|---|---|---|---|---|
272Rg | 111 | 161 | 272.15327(25)# | 2.0(8) ms [3.8(+14−8) ms] |
α | 268Mt | 5+#,6+# |
274Rg[n 2] | 111 | 163 | 274.15525(19)# | 6.4(+307−29) ms | α | 270Mt | |
278Rg[n 3] | 111 | 167 | 278.16149(38)# | 4.2(+75−17) ms | α | 274Mt | |
279Rg[n 4] | 111 | 168 | 279.16272(51)# | 0.17(+81−8) s | α | 275Mt | |
280Rg[n 5] | 111 | 169 | 280.16514(61)# | 3.6(+43−13) s | α (87%) | 276Mt | |
EC (13%)[1] | 280Ds | ||||||
281Rg[n 6] | 111 | 170 | 281.16636(89)# | 17 (+6−3) s[2] | SF (90%) | (various) | |
α (10%) | 277Mt[2] | ||||||
282Rg[n 7] | 111 | 171 | 282.16912(72)# | 2.1 (+1.4-0.6) min[3] | α | 278Mt |
- ↑ Abbreviations:
SF: Spontaneous fission - ↑ Not directly synthesized, occurs as a decay product of 278Nh
- ↑ Not directly synthesized, occurs as a decay product of 282Nh
- ↑ Not directly synthesized, occurs in decay chain of 287Mc
- ↑ Not directly synthesized, occurs in decay chain of 288Mc
- ↑ Not directly synthesized, occurs in decay chain of 293Ts
- ↑ Not directly synthesized, occurs in decay chain of 294Ts
Notes
- Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
- Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties.
Isotopes and nuclear properties
Nucleosynthesis
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.[4]
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.[5] 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.[4] The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion).[6]
Cold fusion
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.[7] A further 3 atoms were synthesized in 2002.[8] The discovery of roentgenium was confirmed in 2003 when a team at RIKEN measured the decays of 14 atoms of 272Rg.[9]
The same roentgenium isotope was also observed by an American team at the Lawrence Berkeley National Laboratory (LBNL) from the reaction:
- 208
82Pb
+ 65
29Cu
→ 272
111Rg
+
n
This reaction was conducted as part of their study of projectiles with odd atomic number in cold fusion reactions.[10]
As decay product
Evaporation residue | Observed roentgenium isotope |
---|---|
294Ts, 290Mc, 286Nh | 282Rg[11] |
293Ts, 289Mc, 285Nh | 281Rg[11] |
288Mc, 284Nh | 280Rg[12] |
287Mc, 283Nh | 279Rg[12] |
282Nh | 278Rg[12] |
278Nh | 274Rg[13] |
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; all of them undergo alpha decays to become roentgenium nuclei, with mass numbers between 274 and 282. Parent nihonium nuclei can be themselves decay products of moscovium or tennessine. To date, no other elements have been known to decay to roentgenium.[14] 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:[11]
- 293
117Ts
→ 289
115Mc
+ 4
2He - 289
115Mc
→ 285
113Nh
+ 4
2He - 285
113Nh
→ 281
111Rg
+ 4
2He
Nuclear isomerism
- 274Rg
Two atoms of 274Rg have been observed in the decay chain of 278Uut. 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.[13]
- 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.[7][9]
Chemical yields of isotopes
Cold fusion
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.
Projectile | Target | CN | 1n | 2n | 3n |
---|---|---|---|---|---|
64Ni | 209Bi | 273Rg | 3.5 pb, 12.5 MeV | ||
65Cu | 208Pb | 273Rg | 1.7 pb, 13.2 MeV |
References
- ↑ http://xxx.lanl.gov/pdf/1502.03030.pdf
- 1 2 Oganessian, Yu. Ts.; et al. (2013). "Experimental studies of the 249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope 277Mt". Physical Review C. 87 (5): 054621. Bibcode:2013PhRvC..87e4621O. doi:10.1103/PhysRevC.87.054621.
- ↑ Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E.; et al. (2014). "48Ca+249Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying 270Db and Discovery of 266Lr". Physical Review Letters. 112 (17): 172501. Bibcode:2014PhRvL.112q2501K. doi:10.1103/PhysRevLett.112.172501.
- 1 2 Armbruster, Peter & Munzenberg, Gottfried (1989). "Creating superheavy elements". Scientific American. 34: 36–42.
- ↑ Barber, Robert C.; Gäggeler, Heinz W.; Karol, Paul J.; Nakahara, Hiromichi; Vardaci, Emanuele; Vogt, Erich (2009). "Discovery of the element with atomic number 112 (IUPAC Technical Report)". Pure and Applied Chemistry. 81 (7): 1331. doi:10.1351/PAC-REP-08-03-05.
- ↑ Fleischmann, Martin; Pons, Stanley (1989). "Electrochemically induced nuclear fusion of deuterium". Journal of Electroanalytical Chemistry and Interfacial Electrochemistry. Elsevier. 261 (2): 301–308. doi:10.1016/0022-0728(89)80006-3. Retrieved 15 October 2012.
- 1 2 Hofmann, S.; Ninov, V.; Heßberger, F. P.; Armbruster, P.; Folger, H.; Münzenberg, G.; Schött, H. J.; Popeko, A. G.; et al. (1995). "The new element 111". Zeitschrift für Physik A. 350 (4): 281–282. Bibcode:1995ZPhyA.350..281H. doi:10.1007/BF01291182.
- ↑ Hofmann, S.; Heßberger, F. P.; Ackermann, D.; Münzenberg, G.; Antalic, S.; Cagarda, P.; Kindler, B.; Kojouharova, J.; et al. (2002). "New results on elements 111 and 112". The European Physical Journal A. 14 (2): 147–157. doi:10.1140/epja/i2001-10119-x.
- 1 2 Morita, K.; Morimoto, K. K.; Kaji, D.; Goto, S.; Haba, H.; Ideguchi, E.; Kanungo, R.; Katori, K.; Koura, H.; Kudo, H.; Ohnishi, T.; Ozawa, A.; Peter, J. C.; Suda, T.; Sueki, K.; Tanihata, I.; Tokanai, F.; Xu, H.; Yeremin, A. V.; Yoneda, A.; Yoshida, A.; Zhao, Y.-L.; Zheng, T. (2004). "Status of heavy element research using GARIS at RIKEN". Nuclear Physics A. 734: 101–108. doi:10.1016/j.nuclphysa.2004.01.019.
- ↑ Folden, C. M.; Gregorich, K.; Düllmann, Ch.; Mahmud, H.; Pang, G.; Schwantes, J.; Sudowe, R.; Zielinski, P.; et al. (2004). "Development of an Odd-Z-Projectile Reaction for Heavy Element Synthesis: 208Pb(64Ni,n)271Ds and 208Pb(65Cu,n)272111". Physical Review Letters. 93 (21): 212702. Bibcode:2004PhRvL..93u2702F. doi:10.1103/PhysRevLett.93.212702. PMID 15601003.
- 1 2 3 Oganessian, Yuri Ts.; Abdullin, F. Sh.; Bailey, P. D.; et al. (2010-04-09). "Synthesis of a New Element with Atomic Number Z=117". Physical Review Letters. American Physical Society. 104 (142502): 142502. Bibcode:2010PhRvL.104n2502O. doi:10.1103/PhysRevLett.104.142502. PMID 20481935.
- 1 2 3 Oganessian, Yu. Ts.; Penionzhkevich, Yu. E.; Cherepanov, E. A. (2007). "AIP Conference Proceedings". 912: 235. doi:10.1063/1.2746600.
|chapter=
ignored (help) - 1 2 Morita, Kosuke; Morimoto, Kouji; Kaji, Daiya; Akiyama, Takahiro; Goto, Sin-ichi; Haba, Hiromitsu; Ideguchi, Eiji; Kanungo, Rituparna; Katori, Kenji; Koura, Hiroyuki; Kudo, Hisaaki; Ohnishi, Tetsuya; Ozawa, Akira; Suda, Toshimi; Sueki, Keisuke; Xu, HuShan; Yamaguchi, Takayuki; Yoneda, Akira; Yoshida, Atsushi; Zhao, YuLiang (2004). "Experiment on the Synthesis of Element 113 in the Reaction 209Bi(70Zn,n)278113". Journal of the Physical Society of Japan. 73 (10): 2593–2596. Bibcode:2004JPSJ...73.2593M. doi:10.1143/JPSJ.73.2593.
- ↑ Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. Retrieved 2008-06-06.
- Isotope masses from:
- M. Wang; G. Audi; A. H. Wapstra; F. G. Kondev; M. MacCormick; X. Xu; et al. (2012). "The AME2012 atomic mass evaluation (II). Tables, graphs and references." (PDF). Chinese Physics C. 36 (12): 1603–2014. Bibcode:2012ChPhC..36....3M. doi:10.1088/1674-1137/36/12/003.
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
- Isotopic compositions and standard atomic masses from:
- J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
- Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005. Check date values in:
|access-date=
(help) - N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.
- Yu. Ts. Oganessian (2007). "Heaviest nuclei from 48Ca-induced reactions". Journal of Physics G. 34 (4): R165–R242. Bibcode:2007JPhG...34..165O. doi:10.1088/0954-3899/34/4/R01.
Isotopes of darmstadtium | Isotopes of roentgenium | Isotopes of copernicium |
Table of nuclides |
Isotopes of the chemical elements | |||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 H |
2 He | ||||||||||||||||
3 Li |
4 Be |
5 B |
6 C |
7 N |
8 O |
9 F |
10 Ne | ||||||||||
11 Na |
12 Mg |
13 Al |
14 Si |
15 P |
16 S |
17 Cl |
18 Ar | ||||||||||
19 K |
20 Ca |
21 Sc |
22 Ti |
23 V |
24 Cr |
25 Mn |
26 Fe |
27 Co |
28 Ni |
29 Cu |
30 Zn |
31 Ga |
32 Ge |
33 As |
34 Se |
35 Br |
36 Kr |
37 Rb |
38 Sr |
39 Y |
40 Zr |
41 Nb |
42 Mo |
43 Tc |
44 Ru |
45 Rh |
46 Pd |
47 Ag |
48 Cd |
49 In |
50 Sn |
51 Sb |
52 Te |
53 I |
54 Xe |
55 Cs |
56 Ba |
72 Hf |
73 Ta |
74 W |
75 Re |
76 Os |
77 Ir |
78 Pt |
79 Au |
80 Hg |
81 Tl |
82 Pb |
83 Bi |
84 Po |
85 At |
86 Rn | |
87 Fr |
88 Ra |
104 Rf |
105 Db |
106 Sg |
107 Bh |
108 Hs |
109 Mt |
110 Ds |
111 Rg |
112 Cn |
113 Nh |
114 Fl |
115 Mc |
116 Lv |
117 Ts |
118 Og | |
57 La |
58 Ce |
59 Pr |
60 Nd |
61 Pm |
62 Sm |
63 Eu |
64 Gd |
65 Tb |
66 Dy |
67 Ho |
68 Er |
69 Tm |
70 Yb |
71 Lu | |||
89 Ac |
90 Th |
91 Pa |
92 U |
93 Np |
94 Pu |
95 Am |
96 Cm |
97 Bk |
98 Cf |
99 Es |
100 Fm |
101 Md |
102 No |
103 Lr | |||
|