Lead-211m

Properties and data of the isotope ^211mPb.

Contents

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

General data

Name of the isotope:Lead-211m; Pb-211mSymbol:^211mPb or 211m82PbMass number A:211 (= number of nucleons)Atomic number Z:82 (= number of protons)Neutrons N:129Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.5731707317073 (= neutron-proton ratio)Neutron excess (N-Z):47Excitation energy:1679.1+x keVIsotopic mass:210.9887354(24) u (atomic weight of Lead-211m)Nuclide mass:210.943757 u (calculated nuclear mass without electrons)Mass excess:-10.49291 MeVMass defect:1.770691388 u (per nucleus)Nuclear binding energy:1649.38840377 MeV (per nucleus)
7.81700665 MeV (average binding energy per nucleon)Half-life:159(28) nsDecay constant λ:4359416.2299368 s^-1Specific activity α:1.250143743036 × 10⁺²⁸ Bq g^-1
3.378766873072 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)(27/2+)

Radioactive Decay

Half-life T_½ = 159(28) ns respectively 1.59 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	²¹¹Pb	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
²¹¹Pb		36.1(2) min	9/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 129) and isobaric (same nucleon number A = 211) with Lead-211m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 129	Isobar A = 211
78	²⁰⁷Pt
79	²⁰⁸Au
80	²⁰⁹Hg	²¹¹Hg
81	²¹⁰Tl	²¹¹Tl
82	²¹¹Pb	²¹¹Pb
83	²¹²Bi	²¹¹Bi
84	²¹³Po	²¹¹Po
85	²¹⁴At	²¹¹At
86	²¹⁵Rn	²¹¹Rn
87	²¹⁶Fr	²¹¹Fr
88	²¹⁷Ra	²¹¹Ra
89	²¹⁸Ac	²¹¹Ac
90	²¹⁹Th	²¹¹Th
91	²²⁰Pa
92	²²¹U
93	²²²Np