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Isotopes of roentgenium

Roentgenium (Rg) has no stable isotopes. A standard atomic mass cannot be given.

Roentgenium has also been called eka-gold.


Z(p) N(n)  
isotopic mass (u)
half-life nuclear
(mole fraction)
range of natural
(mole fraction)
excitation energy
272Rg 111 161 272.15362(36)# 2.0(8) ms [3.8(+14-8) ms] 5+#,6+#
273Rg 111 162 273.15368(65)# 5# ms
274Rg 111 163 274.15571(66)# 6.4(+307-29) ms
275Rg 111 164 275.15614(74)# 10# ms
276Rg 111 165 276.15849(67)# 100# ms
277Rg 111 166 277.15952(66)# 1# s
278Rg 111 167 278.16160(68)# 1# s
279Rg 111 168 279.16247(71)# 0.17(+81-8) s
280Rg 111 169 280.16447(80)# 3.6(+43-13) s
281Rg 111 170 281.16537(100)# 1# min
282Rg 111 171 282.16749(95)# 4# min
283Rg 111 172 283.16842(84)# 10# min


  • 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.


  • Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
  • Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
  • Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
    • Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
    • National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
    • David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.

Isotopes of darmstadtium Isotopes of roentgenium Isotopes of ununbium
Index to isotope pages
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isotopes_of_roentgenium". A list of authors is available in Wikipedia.
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