Bismuth-207

Properties and data of the isotope ²⁰⁷Bi.

Contents

General data

Name of the isotope:Bismuth-207; Bi-207Symbol:²⁰⁷Bi or 20783BiMass number A:207 (= number of nucleons)Atomic number Z:83 (= number of protons)Neutrons N:124Isotopic mass:206.9784705(26) u (atomic weight of Bismuth-207)Nuclide mass:206.9329436 u (calculated nuclear mass without electrons)Mass excess:-20.0546 MeVMass defect:1.74545674 u (per nucleus)Nuclear binding energy:1625.88248057 MeV (per nucleus)
7.85450474 MeV (average binding energy per nucleon)Separation energy:S_N = 8.098(8) MeV (first neutron)
S_P = 3.5580(21) MeV (first proton)Half-life:31.55(4) aDecay constant λ:6.966576383998 × 10^-10 s^-1Specific activity α:2036587587181.9 Bq g^-1
55.042907761673 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2-Charge radius:5.5103(907) femtometer fmYear of discovery:1950

Radioactive Decay

Half-life T_½ = 31.55(4) a respectively 9.94961 × 10⁸ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	²⁰⁷Pb	100 %	2.3974(26) MeV

Parent Nuclides

Direct parent isotopes are: ²¹¹At, ²⁰⁷Po.

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
^207mBi	2101.61(16) keV	182(6) μs	21/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 124) and isobaric (same nucleon number A = 207) with Bismuth-207. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 124	Isobar A = 207
75	¹⁹⁹Re
76	²⁰⁰Os
77	²⁰¹Ir
78	²⁰²Pt	²⁰⁷Pt
79	²⁰³Au	²⁰⁷Au
80	²⁰⁴Hg	²⁰⁷Hg
81	²⁰⁵Tl	²⁰⁷Tl
82	²⁰⁶Pb	²⁰⁷Pb
83	²⁰⁷Bi	²⁰⁷Bi
84	²⁰⁸Po	²⁰⁷Po
85	²⁰⁹At	²⁰⁷At
86	²¹⁰Rn	²⁰⁷Rn
87	²¹¹Fr	²⁰⁷Fr
88	²¹²Ra	²⁰⁷Ra
89	²¹³Ac	²⁰⁷Ac
90	²¹⁴Th	²⁰⁷Th
91	²¹⁵Pa
92	²¹⁶U