Lead-199

Properties and data of the isotope ¹⁹⁹Pb.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Lead-199; Pb-199Symbol:¹⁹⁹Pb or 19982PbMass number A:199 (= number of nucleons)Atomic number Z:82 (= number of protons)Neutrons N:117Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.4268292682927 (= neutron-proton ratio)Neutron excess (N-Z):35Isotopic mass:198.972913(7) u (atomic weight of Lead-199)Nuclide 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)Separation energy:S_N = 7.236(11) MeV (first neutron)
S_P = 4.992(10) MeV (first proton)Half-life:90(10) minDecay constant λ:0.00012836058899258 s^-1Specific activity α:3.88497873049 × 10⁺¹⁷ Bq g^-1
10499942.514854 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-Magnetic dipole moment:μ(μ_N) = - 1.0742(12)Quadrupole moment Q:+0.08(9) barn (100 fm²)Nuclear g-factor:g_l = -0.71613333333333Charge radius:5..4529(22) femtometer fmYear of discovery:1950

Radioactive Decay

Half-life T_½ = 90(10) min (minutes) respectively 5.400 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β⁺	¹⁹⁹Tl	100 %	2.828(29) MeV

Parent Nuclides

Direct parent isotopes are: ¹⁹⁹Bi, ²⁰³Po.

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
^199m1Pb	424.8(2)+x keV	12.2(3) min	(13/2+)
^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-199. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	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