Lead-206

Properties and data of the isotope ²⁰⁶Pb.

Contents

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

General data

Name of the isotope:Lead-206; Pb-206Other names:Radium G. UranbleiSymbol:²⁰⁶Pb or 20682PbMass number A:206 (= number of nucleons)Atomic number Z:82 (= number of protons)Neutrons N:124Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.5121951219512 (= neutron-proton ratio)Neutron excess (N-Z):42Isotopic mass:205.974466(8) u (atomic weight of Lead-206)Nuclide mass:205.9294876 u (calculated nuclear mass without electrons)Mass excess:-23.78477 MeVMass defect:1.741636208 u (per nucleus)Nuclear binding energy:1622.32367793 MeV (per nucleus)
7.87535766 MeV (average binding energy per nucleon)Separation energy:S_N = 8.08666(6) MeV (first neutron)
S_P = 7.2537(5) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)0+Charge radius:5.4902(14) femtometer fmYear of discovery:1927

Parent Nuclides

Direct parent isotopes are: ²⁰⁶Bi, ²¹⁰Po, ²⁰⁶Tl.

Occurrence

Comparison of the natural Lead isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Lead Isotopic mixture	207.2 u	100 %
Isotope ²⁰⁶Pb	205.974466(8) u	24.1(30) %	stable	0+
Isotope ²⁰⁴Pb	203.973044(8) u	1.4(6) %	1.4 × 10¹⁷ a	0+
Isotope ²⁰⁸Pb	207.976653(8) u	52.4(70) %	stable	0+
Isotope ²⁰⁷Pb	206.975897(8) u	22.1(50) %	stable	1/2-

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
^206m1Pb	2200.16(4) keV	125(2) μs	7-
^206m2Pb	4027.3(3) keV	202(3) ns	12+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 124) and isobaric (same nucleon number A = 206) with Lead-206. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 124	Isobar A = 206
75	¹⁹⁹Re
76	²⁰⁰Os
77	²⁰¹Ir
78	²⁰²Pt	²⁰⁶Pt
79	²⁰³Au	²⁰⁶Au
80	²⁰⁴Hg	²⁰⁶Hg
81	²⁰⁵Tl	²⁰⁶Tl
82	²⁰⁶Pb	²⁰⁶Pb
83	²⁰⁷Bi	²⁰⁶Bi
84	²⁰⁸Po	²⁰⁶Po
85	²⁰⁹At	²⁰⁶At
86	²¹⁰Rn	²⁰⁶Rn
87	²¹¹Fr	²⁰⁶Fr
88	²¹²Ra	²⁰⁶Ra
89	²¹³Ac	²⁰⁶Ac
90	²¹⁴Th
91	²¹⁵Pa
92	²¹⁶U