Bismuth-208m

Properties and data of the isotope ^208mBi.

Contents

General data

Name of the isotope:Bismuth-208m; Bi-208mSymbol:^208mBi or 208m83BiMass number A:208 (= number of nucleons)Atomic number Z:83 (= number of protons)Neutrons N:125Isotopic mass:207.9797420(25) u (atomic weight of Bismuth-208m)
Excitation energy: 1571.1(4) keVNuclide mass:207.9342151 u (calculated nuclear mass without electrons)Mass excess:-18.87021 MeVMass defect:1.752850156 u (per nucleus)Nuclear binding energy:1632.76940321 MeV (per nucleus)
7.8498529 MeV (average binding energy per nucleon)Half-life:2.58(4) msDecay constant λ:268.66169789145 s^-1Specific activity α:7.816031827884 × 10⁺²³ Bq g^-1
21124410345634 Ci g^-1Spin and parity:
(nuclear angular momentum)10-Magnetic dipole moment:μ(μ_N) = 2.672(14)Nuclear g-factor:g_l = 0.2672

Radioactive Decay

Half-life T_½ = 2.58(4) ms respectively 2.58 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	²⁰⁸Bi	100 %

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
²⁰⁸Bi		3.68(4) × 10⁵ a	5+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 125) and isobaric (same nucleon number A = 208) with Bismuth-208m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 125	Isobar A = 208
76	²⁰¹Os
77	²⁰²Ir
78	²⁰³Pt	²⁰⁸Pt
79	²⁰⁴Au	²⁰⁸Au
80	²⁰⁵Hg	²⁰⁸Hg
81	²⁰⁶Tl	²⁰⁸Tl
82	²⁰⁷Pb	²⁰⁸Pb
83	²⁰⁸Bi	²⁰⁸Bi
84	²⁰⁹Po	²⁰⁸Po
85	²¹⁰At	²⁰⁸At
86	²¹¹Rn	²⁰⁸Rn
87	²¹²Fr	²⁰⁸Fr
88	²¹³Ra	²⁰⁸Ra
89	²¹⁴Ac	²⁰⁸Ac
90	²¹⁵Th	²⁰⁸Th
91	²¹⁶Pa
92	²¹⁷U