Lead-186

Properties and data of the isotope ¹⁸⁶Pb.

Content

General data

Name of the isotope:Lead-186; Pb-186Symbol:¹⁸⁶Pb or 18682PbMass number A:186 (= number of nucleons)Atomic number Z:82 (= number of protons)Neutrons N:104Isotopic mass:185.984238(12) u (atomic weight of Lead-186)Nuclide mass:185.9392596 u (calculated nuclear mass without electrons)Mass excess:-14.68221 MeVMass defect:1.558565888 u (per nucleus)Nuclear binding energy:1451.79477328 MeV (per nucleus)
7.80534824 MeV (average binding energy per nucleon)Separation energy:S_N = 11.212(20) MeV (first neutron)
S_P = 2.213(24) MeV (first proton)Half-life:4.82(3) sDecay constant λ:0.14380646899584 s^-1Specific activity α:4.681204393854 × 10⁺²⁰ Bq g^-1
12651903767.174 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:5.4027(27) femtometer fmYear of discovery:1972

Radioactive Decay

Half-life T_½ = 4.82(3) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁸²Hg	40(8) %	6.47(6) MeV
β⁺	¹⁸⁶Tl	60(8) %	5.205(25) MeV

Parent Nuclides

Direct parent isotope is: ¹⁹⁰Po.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 104) and isobaric (same nucleon number A = 186) with Lead-186. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 104	Isobar A = 186
62	¹⁶⁶Sm
63	¹⁶⁷Eu
64	¹⁶⁸Gd
65	¹⁶⁹Tb
66	¹⁷⁰Dy
67	¹⁷¹Ho
68	¹⁷²Er
69	¹⁷³Tm
70	¹⁷⁴Yb
71	¹⁷⁵Lu	¹⁸⁶Lu
72	¹⁷⁶Hf	¹⁸⁶Hf
73	¹⁷⁷Ta	¹⁸⁶Ta
74	¹⁷⁸W	¹⁸⁶W
75	¹⁷⁹Re	¹⁸⁶Re
76	¹⁸⁰Os	¹⁸⁶Os
77	¹⁸¹Ir	¹⁸⁶Ir
78	¹⁸²Pt	¹⁸⁶Pt
79	¹⁸³Au	¹⁸⁶Au
80	¹⁸⁴Hg	¹⁸⁶Hg
81	¹⁸⁵Tl	¹⁸⁶Tl
82	¹⁸⁶Pb	¹⁸⁶Pb
83	¹⁸⁷Bi	¹⁸⁶Bi
84	¹⁸⁸Po	¹⁸⁶Po