Lead-199m1

Properties and data of the isotope ¹⁹⁹Pb.

Content

General data

Name of the isotope:Lead-199m1; Pb-199m1Symbol:¹⁹⁹Pb or 19982PbMass number A:199 (= number of nucleons)Atomic number Z:82 (= number of protons)Neutrons N:117Isotopic mass:198.972913(11) u (atomic weight of Lead-199m1)
Excitation energy: 424.8(2)+x keVNuclide mass:198.9279346 u (calculated nuclear mass without electrons)Mass excess:-25.23138 MeVMass defect:1.682534796 u (per nucleus)Nuclear binding energy:1567.27106727 MeV (per nucleus)
7.87573401 MeV (average binding energy per nucleon)Half-life:12.2(3) minDecay constant λ:0.00094692237781413 s^-1Specific activity α:2.880050476072 × 10⁺¹⁸ Bq g^-1
77839202.056005 Ci g^-1Spin and parity:
(nuclear angular momentum)(13/2+)

Radioactive Decay

Half-life T_½ = 12.2(3) min (minutes) respectively 7.32 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹⁹⁹Pb	93 %
β⁺	¹⁹⁹Tl	7 %

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
¹⁹⁹Pb		90(10) min	3/2-
^199m2Pb	2559.7(4)+x keV	10.1(2) μs	(29/2-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 117) and isobaric (same nucleon number A = 199) with Lead-199m1. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 117	Isobar A = 199
71	¹⁸⁸Lu
72	¹⁸⁹Hf
73	¹⁹⁰Ta
74	¹⁹¹W
75	¹⁹²Re	¹⁹⁹Re
76	¹⁹³Os	¹⁹⁹Os
77	¹⁹⁴Ir	¹⁹⁹Ir
78	¹⁹⁵Pt	¹⁹⁹Pt
79	¹⁹⁶Au	¹⁹⁹Au
80	¹⁹⁷Hg	¹⁹⁹Hg
81	¹⁹⁸Tl	¹⁹⁹Tl
82	¹⁹⁹Pb	¹⁹⁹Pb
83	²⁰⁰Bi	¹⁹⁹Bi
84	²⁰¹Po	¹⁹⁹Po
85	²⁰²At	¹⁹⁹At
86	²⁰³Rn	¹⁹⁹Rn
87	²⁰⁴Fr	¹⁹⁹Fr
88	²⁰⁵Ra
89	²⁰⁶Ac
90	²⁰⁷Th