Lead-207m

Properties and data of the isotope ^207mPb.

Contents

See also: List of individual Lead isotopes (and general data sources).

General data

Name of the isotope:Lead-207m; Pb-207mSymbol:^207mPb or 207m82PbMass number A:207 (= number of nucleons)Atomic number Z:82 (= number of protons)Neutrons N:125Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.5243902439024 (= neutron-proton ratio)Neutron excess (N-Z):43Excitation energy:1633.356(4) keVIsotopic mass:206.975897(8) u (atomic weight of Lead-207m)Nuclide mass:206.9309186 u (calculated nuclear mass without electrons)Mass excess:-22.4518 MeVMass defect:1.748870124 u (per nucleus)Nuclear binding energy:1629.06202729 MeV (per nucleus)
7.86986487 MeV (average binding energy per nucleon)Half-life:806(5) msDecay constant λ:0.85998409498753 s^-1Specific activity α:2.514051144330 × 10⁺²¹ Bq g^-1
67947328225.138 Ci g^-1Spin and parity:
(nuclear angular momentum)13/2+

Radioactive Decay

Half-life T_½ = 806(5) ms respectively 8.06 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	²⁰⁷Pb	100 %	1.632 MeV

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
²⁰⁷Pb		stable	1/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 125) and isobaric (same nucleon number A = 207) with Lead-207m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

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