Roentgenium-281

Properties and data of the isotope ²⁸¹Rg.

Content

General data

Name of the isotope:Roentgenium-281; Rg-281Symbol:²⁸¹Rg or 281111RgMass number A:281 (= number of nucleons)Atomic number Z:111 (= number of protons)Neutrons N:170Isotopic mass:281.16676(83) u (atomic weight of Roentgenium-281)Nuclide mass:281.105878 u (calculated nuclear mass without electrons)Mass excess:155.33594 MeVMass defect:2.174854272 u (per nucleus)Nuclear binding energy:2025.86370524 MeV (per nucleus)
7.20947938 MeV (average binding energy per nucleon)Separation energy:S_N = 6.624(939) MeV (first neutron)
S_P = 2.276(1076) MeV (first proton)Half-life:15 sDecay constant λ:0.04620981203733 s^-1Specific activity α:9.903273921708 × 10⁺¹⁹ Bq g^-1
2676560519.3806 Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:2010

Radioactive Decay

Half-life T_½ = 15 s respectively 1.5 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
SZ	div	82 %
α	²⁷⁷Mt	18 %	9.9(4) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 170) and isobaric (same nucleon number A = 281) with Roentgenium-281. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.