Lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, ...

(₈₂Pb) has four stable

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers ( mass num ...

s: ²⁰⁴Pb, ²⁰⁶Pb, ²⁰⁷Pb, ²⁰⁸Pb. Lead-204 is entirely a

primordial nuclide In geochemistry, geophysics and nuclear physics, primordial nuclides, also known as primordial isotopes, are nuclides found on Earth that have existed in their current form since before Earth was formed. Primordial nuclides were present in the ...

and is not a radiogenic nuclide. The three isotopes lead-206, lead-207, and lead-208 represent the ends of three

decay chain In nuclear science, the decay chain refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations. It is also known as a "radioactive cascade". Most radioisotopes do not decay dire ...

s: the uranium series (or radium series), the actinium series, and the

thorium series In nuclear science, the decay chain refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations. It is also known as a "radioactive cascade". Most radioisotopes do not decay direct ...

, respectively; a fourth decay chain, the neptunium series, terminates with the

thallium Thallium is a chemical element with the symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes an ...

isotope ²⁰⁵Tl. The three series terminating in lead represent the decay chain products of long-lived primordial ²³⁸U, ²³⁵U, and ²³²Th, respectively. However, each of them also occurs, to some extent, as primordial isotopes that were made in supernovae, rather than radiogenically as daughter products. The fixed ratio of lead-204 to the primordial amounts of the other lead isotopes may be used as the baseline to estimate the extra amounts of radiogenic lead present in rocks as a result of decay from uranium and thorium. (See

lead–lead dating Lead–lead dating is a method for dating geological samples, normally based on 'whole-rock' samples of material such as granite. For most dating requirements it has been superseded by uranium–lead dating (U–Pb dating), but in certain special ...

and uranium–lead dating). The longest-lived radioisotopes are ²⁰⁵Pb with a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ...

of 17.3 million years and ²⁰²Pb with a half-life of 52,500 years. A shorter-lived naturally occurring radioisotope, ²¹⁰Pb with a half-life of 22.2 years, is useful for studying the

sedimentation Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...

chronology of environmental samples on time scales shorter than 100 years. The relative abundances of the four stable isotopes are approximately 1.5%, 24%, 22%, and 52.5%, combining to give a

standard atomic weight The standard atomic weight of a chemical element (symbol ''A''r°(E) for element "E") is the weighted arithmetic mean of the relative isotopic masses of all isotopes of that element weighted by each isotope's abundance on Earth. For example, ...

(abundance-weighted average of the stable isotopes) of 207.2(1). Lead is the element with the heaviest stable isotope, ²⁰⁸Pb. (The more massive ²⁰⁹Bi, long considered to be stable, actually has a half-life of 2.01×10¹⁹ years.) ²⁰⁸Pb is also a doubly magic isotope, as it has 82

proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...

s and 126

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the atomic nucleus, nuclei of atoms. Since protons and ...

s. It is the heaviest doubly magic nuclide known. A total of 43 lead isotopes are now known, including very unstable synthetic species. The four primordial isotopes of lead are all observationally stable, meaning that they are predicted to undergo radioactive decay but no decay has been observed yet. These four isotopes are predicted to undergo

alpha decay Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays' into a different atomic nucleus, with a mass number that is reduced by four and an at ...

and become isotopes of mercury which are themselves radioactive or observationally stable. In its fully ionized state, the isotope ²⁰⁵Pb also becomes stable.

List of isotopes

, - , ¹⁷⁸Pb , , style="text-align:right" , 82 , style="text-align:right" , 96 , 178.003830(26) , 0.23(15) ms , α , ¹⁷⁴Hg , 0+ , , , - , ¹⁷⁹Pb , , style="text-align:right" , 82 , style="text-align:right" , 97 , 179.00215(21)# , 3.9(1.1) ms , α , ¹⁷⁵Hg , (9/2−) , , , - , ¹⁸⁰Pb , , style="text-align:right" , 82 , style="text-align:right" , 98 , 179.997918(22) , 4.5(11) ms , α , ¹⁷⁶Hg , 0+ , , , - , rowspan=2, ¹⁸¹Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 99 , rowspan=2, 180.99662(10) , rowspan=2, 45(20) ms , α (98%) , ¹⁷⁷Hg , rowspan=2, (9/2−) , rowspan=2, , rowspan=2, , - , β⁺ (2%) , ¹⁸¹Tl , - , rowspan=2, ¹⁸²Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 100 , rowspan=2, 181.992672(15) , rowspan=2, 60(40) ms
5(+40−35) ms, α (98%) , ¹⁷⁸Hg , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺ (2%) , ¹⁸²Tl , - , rowspan=2, ¹⁸³Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 101 , rowspan=2, 182.99187(3) , rowspan=2, 535(30) ms , α (94%) , ¹⁷⁹Hg , rowspan=2, (3/2−) , rowspan=2, , rowspan=2, , - , β⁺ (6%) , ¹⁸³Tl , - , rowspan=2 style="text-indent:1em" , ^183mPb , rowspan=2, , rowspan=2 colspan="3" style="text-indent:2em" , 94(8) keV , rowspan=2, 415(20) ms , α , ¹⁷⁹Hg , rowspan=2, (13/2+) , rowspan=2, , rowspan=2, , - , β⁺ (rare) , ¹⁸³Tl , - , rowspan=2, ¹⁸⁴Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 102 , rowspan=2, 183.988142(15) , rowspan=2, 490(25) ms , α , ¹⁸⁰Hg , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺ (rare) , ¹⁸⁴Tl , - , rowspan=2, ¹⁸⁵Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 103 , rowspan=2, 184.987610(17) , rowspan=2, 6.3(4) s , α , ¹⁸¹Hg , rowspan=2, 3/2− , rowspan=2, , rowspan=2, , - , β⁺ (rare) , ¹⁸⁵Tl , - , rowspan=2 style="text-indent:1em" , ^185mPb , rowspan=2, , rowspan=2 colspan="3" style="text-indent:2em" , 60(40)# keV , rowspan=2, 4.07(15) s , α , ¹⁸¹Hg , rowspan=2, 13/2+ , rowspan=2, , rowspan=2, , - , β⁺ (rare) , ¹⁸⁵Tl , - , rowspan=2, ¹⁸⁶Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 104 , rowspan=2, 185.984239(12) , rowspan=2, 4.82(3) s , α (56%) , ¹⁸²Hg , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , β⁺ (44%) , ¹⁸⁶Tl , - , rowspan=2, ¹⁸⁷Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 105 , rowspan=2, 186.983918(9) , rowspan=2, 15.2(3) s , β⁺ , ¹⁸⁷Tl , rowspan=2, (3/2−) , rowspan=2, , rowspan=2, , - , α , ¹⁸³Hg , - , rowspan=2 style="text-indent:1em" , ^187mPb , rowspan=2, , rowspan=2 colspan="3" style="text-indent:2em" , 11(11) keV , rowspan=2, 18.3(3) s , β⁺ (98%) , ¹⁸⁷Tl , rowspan=2, (13/2+) , rowspan=2, , rowspan=2, , - , α (2%) , ¹⁸³Hg , - , rowspan=2, ¹⁸⁸Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 106 , rowspan=2, 187.980874(11) , rowspan=2, 25.5(1) s , β⁺ (91.5%) , ¹⁸⁸Tl , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , α (8.5%) , ¹⁸⁴Hg , - , style="text-indent:1em" , ^188m1Pb , , colspan="3" style="text-indent:2em" , 2578.2(7) keV , 830(210) ns , , , (8−) , , , - , style="text-indent:1em" , ^188m2Pb , , colspan="3" style="text-indent:2em" , 2800(50) keV , 797(21) ns , , , , , , - , ¹⁸⁹Pb , , style="text-align:right" , 82 , style="text-align:right" , 107 , 188.98081(4) , 51(3) s , β⁺ , ¹⁸⁹Tl , (3/2−) , , , - , rowspan=2 style="text-indent:1em" , ^189m1Pb , rowspan=2, , rowspan=2 colspan="3" style="text-indent:2em" , 40(30)# keV , rowspan=2, 50.5(2.1) s , β⁺ (99.6%) , ¹⁸⁹Tl , rowspan=2, 13/2+ , rowspan=2, , rowspan=2, , - , α (.4%) , ¹⁸⁵Hg , - , style="text-indent:1em" , ^189m2Pb , , colspan="3" style="text-indent:2em" , 2475(30)# keV , 26(5) μs , , , (10)+ , , , - , rowspan=2, ¹⁹⁰Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 108 , rowspan=2, 189.978082(13) , rowspan=2, 71(1) s , β⁺ (99.1%) , ¹⁹⁰Tl , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , α (.9%) , ¹⁸⁶Hg , - , style="text-indent:1em" , ^190m1Pb , , colspan="3" style="text-indent:2em" , 2614.8(8) keV , 150 ns , , , (10)+ , , , - , style="text-indent:1em" , ^190m2Pb , , colspan="3" style="text-indent:2em" , 2618(20) keV , 25 μs , , , (12+) , , , - , style="text-indent:1em" , ^190m3Pb , , colspan="3" style="text-indent:2em" , 2658.2(8) keV , 7.2(6) μs , , , (11)− , , , - , rowspan=2, ¹⁹¹Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 109 , rowspan=2, 190.97827(4) , rowspan=2, 1.33(8) min , β⁺ (99.987%) , ¹⁹¹Tl , rowspan=2, (3/2−) , rowspan=2, , rowspan=2, , - , α (.013%) , ¹⁸⁷Hg , - , rowspan=2 style="text-indent:1em" , ^191mPb , rowspan=2, , rowspan=2 colspan="3" style="text-indent:2em" , 20(50) keV , rowspan=2, 2.18(8) min , β⁺ (99.98%) , ¹⁹¹Tl , rowspan=2, 13/2(+) , rowspan=2, , rowspan=2, , - , α (.02%) , ¹⁸⁷Hg , - , rowspan=2, ¹⁹²Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 110 , rowspan=2, 191.975785(14) , rowspan=2, 3.5(1) min , β⁺ (99.99%) , ¹⁹²Tl , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , α (.0061%) , ¹⁸⁸Hg , - , style="text-indent:1em" , ^192m1Pb , , colspan="3" style="text-indent:2em" , 2581.1(1) keV , 164(7) ns , , , (10)+ , , , - , style="text-indent:1em" , ^192m2Pb , , colspan="3" style="text-indent:2em" , 2625.1(11) keV , 1.1(5) μs , , , (12+) , , , - , style="text-indent:1em" , ^192m3Pb , , colspan="3" style="text-indent:2em" , 2743.5(4) keV , 756(21) ns , , , (11)− , , , - , ¹⁹³Pb , , style="text-align:right" , 82 , style="text-align:right" , 111 , 192.97617(5) , 5# min , β⁺ , ¹⁹³Tl , (3/2−) , , , - , style="text-indent:1em" , ^193m1Pb , , colspan="3" style="text-indent:2em" , 130(80)# keV , 5.8(2) min , β⁺ , ¹⁹³Tl , 13/2(+) , , , - , style="text-indent:1em" , ^193m2Pb , , colspan="3" style="text-indent:2em" , 2612.5(5)+X keV , 135(+25−15) ns , , , (33/2+) , , , - , rowspan=2, ¹⁹⁴Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 112 , rowspan=2, 193.974012(19) , rowspan=2, 12.0(5) min , β⁺ (100%) , ¹⁹⁴Tl , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , α (7.3×10⁻⁶%) , ¹⁹⁰Hg , - , ¹⁹⁵Pb , , style="text-align:right" , 82 , style="text-align:right" , 113 , 194.974542(25) , ~15 min , β⁺ , ¹⁹⁵Tl , 3/2#- , , , - , style="text-indent:1em" , ^195m1Pb , , colspan="3" style="text-indent:2em" , 202.9(7) keV , 15.0(12) min , β⁺ , ¹⁹⁵Tl , 13/2+ , , , - , style="text-indent:1em" , ^195m2Pb , , colspan="3" style="text-indent:2em" , 1759.0(7) keV , 10.0(7) μs , , , 21/2− , , , - , rowspan=2, ¹⁹⁶Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 114 , rowspan=2, 195.972774(15) , rowspan=2, 37(3) min , β⁺ , ¹⁹⁶Tl , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , α (3×10⁻⁵%) , ¹⁹²Hg , - , style="text-indent:1em" , ^196m1Pb , , colspan="3" style="text-indent:2em" , 1049.20(9) keV , <100 ns , , , 2+ , , , - , style="text-indent:1em" , ^196m2Pb , , colspan="3" style="text-indent:2em" , 1738.27(12) keV , <1 μs , , , 4+ , , , - , style="text-indent:1em" , ^196m3Pb , , colspan="3" style="text-indent:2em" , 1797.51(14) keV , 140(14) ns , , , 5− , , , - , style="text-indent:1em" , ^196m4Pb , , colspan="3" style="text-indent:2em" , 2693.5(5) keV , 270(4) ns , , , (12+) , , , - , ¹⁹⁷Pb , , style="text-align:right" , 82 , style="text-align:right" , 115 , 196.973431(6) , 8.1(17) min , β⁺ , ¹⁹⁷Tl , 3/2− , , , - , rowspan=3 style="text-indent:1em" , ^197m1Pb , rowspan=3, , rowspan=3 colspan="3" style="text-indent:2em" , 319.31(11) keV , rowspan=3, 42.9(9) min , β⁺ (81%) , ¹⁹⁷Tl , rowspan=3, 13/2+ , rowspan=3, , rowspan=3, , - , IT (19%) , ¹⁹⁷Pb , - , α (3×10⁻⁴%) , ¹⁹³Hg , - , style="text-indent:1em" , ^197m2Pb , , colspan="3" style="text-indent:2em" , 1914.10(25) keV , 1.15(20) μs , , , 21/2− , , , - , ¹⁹⁸Pb , , style="text-align:right" , 82 , style="text-align:right" , 116 , 197.972034(16) , 2.4(1) h , β⁺ , ¹⁹⁸Tl , 0+ , , , - , style="text-indent:1em" , ^198m1Pb , , colspan="3" style="text-indent:2em" , 2141.4(4) keV , 4.19(10) μs , , , (7)− , , , - , style="text-indent:1em" , ^198m2Pb , , colspan="3" style="text-indent:2em" , 2231.4(5) keV , 137(10) ns , , , (9)− , , , - , style="text-indent:1em" , ^198m3Pb , , colspan="3" style="text-indent:2em" , 2820.5(7) keV , 212(4) ns , , , (12)+ , , , - , ¹⁹⁹Pb , , style="text-align:right" , 82 , style="text-align:right" , 117 , 198.972917(28) , 90(10) min , β⁺ , ¹⁹⁹Tl , 3/2− , , , - , rowspan=2 style="text-indent:1em" , ^199m1Pb , rowspan=2, , rowspan=2 colspan="3" style="text-indent:2em" , 429.5(27) keV , rowspan=2, 12.2(3) min , IT (93%) , ¹⁹⁹Pb , rowspan=2, (13/2+) , rowspan=2, , rowspan=2, , - , β⁺ (7%) , ¹⁹⁹Tl , - , style="text-indent:1em" , ^199m2Pb , , colspan="3" style="text-indent:2em" , 2563.8(27) keV , 10.1(2) μs , , , (29/2−) , , , - , ²⁰⁰Pb , , style="text-align:right" , 82 , style="text-align:right" , 118 , 199.971827(12) , 21.5(4) h , β⁺ , ²⁰⁰Tl , 0+ , , , - , rowspan=2, ²⁰¹Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 119 , rowspan=2, 200.972885(24) , rowspan=2, 9.33(3) h , EC (99%) , rowspan=2, ²⁰¹Tl , rowspan=2, 5/2− , rowspan=2, , rowspan=2, , - , β⁺ (1%) , - , style="text-indent:1em" , ^201m1Pb , , colspan="3" style="text-indent:2em" , 629.14(17) keV , 61(2) s , , , 13/2+ , , , - , style="text-indent:1em" , ^201m2Pb , , colspan="3" style="text-indent:2em" , 2718.5+X keV , 508(5) ns , , , (29/2−) , , , - , rowspan=2, ²⁰²Pb , rowspan=2, , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 120 , rowspan=2, 201.972159(9) , rowspan=2, 5.25(28)×10⁴ y , EC (99%) , ²⁰²Tl , rowspan=2, 0+ , rowspan=2, , rowspan=2, , - , α (1%) , ¹⁹⁸Hg , - , rowspan=2 style="text-indent:1em" , ^202m1Pb , rowspan=2, , rowspan=2 colspan="3" style="text-indent:2em" , 2169.83(7) keV , rowspan=2, 3.53(1) h , IT (90.5%) , ²⁰²Pb , rowspan=2, 9− , rowspan=2, , rowspan=2, , - , EC (9.5%) , ²⁰²Tl , - , style="text-indent:1em" , ^202m2Pb , , colspan="3" style="text-indent:2em" , 4142.9(11) keV , 110(5) ns , , , (16+) , , , - , style="text-indent:1em" , ^202m3Pb , , colspan="3" style="text-indent:2em" , 5345.9(13) keV , 107(5) ns , , , (19−) , , , - , ²⁰³Pb , , style="text-align:right" , 82 , style="text-align:right" , 121 , 202.973391(7) , 51.873(9) h , EC , ²⁰³Tl , 5/2− , , , - , style="text-indent:1em" , ^203m1Pb , , colspan="3" style="text-indent:2em" , 825.20(9) keV , 6.21(8) s , IT , ²⁰³Pb , 13/2+ , , , - , style="text-indent:1em" , ^203m2Pb , , colspan="3" style="text-indent:2em" , 2949.47(22) keV , 480(7) ms , , , 29/2− , , , - , style="text-indent:1em" , ^203m3Pb , , colspan="3" style="text-indent:2em" , 2923.4+X keV , 122(4) ns , , , (25/2−) , , , - , ²⁰⁴PbUsed in

, , style="text-align:right" , 82 , style="text-align:right" , 122 , 203.9730436(13) , colspan="3" style="text-align:center;", Observationally StableBelieved to undergo α decay to ²⁰⁰Hg with a

over 1.4×10²⁰ years , 0+ , 0.014(1) , 0.0104–0.0165 , - , style="text-indent:1em" , ^204m1Pb , , colspan="3" style="text-indent:2em" , 1274.00(4) keV , 265(10) ns , , , 4+ , , , - , style="text-indent:1em" , ^204m2Pb , , colspan="3" style="text-indent:2em" , 2185.79(5) keV , 67.2(3) min , , , 9− , , , - , style="text-indent:1em" , ^204m3Pb , , colspan="3" style="text-indent:2em" , 2264.33(4) keV , 0.45(+10−3) μs , , , 7− , , , - , ²⁰⁵Pb , , style="text-align:right" , 82 , style="text-align:right" , 123 , 204.9744818(13) , 1.73(7)×10⁷ y , EC , ²⁰⁵Tl , 5/2− , , , - , style="text-indent:1em" , ^205m1Pb , , colspan="3" style="text-indent:2em" , 2.329(7) keV , 24.2(4) μs , , , 1/2− , , , - , style="text-indent:1em" , ^205m2Pb , , colspan="3" style="text-indent:2em" , 1013.839(13) keV , 5.55(2) ms , , , 13/2+ , , , - , style="text-indent:1em" , ^205m3Pb , , colspan="3" style="text-indent:2em" , 3195.7(5) keV , 217(5) ns , , , 25/2− , , , - , ²⁰⁶PbFinal

decay product In nuclear physics, a decay product (also known as a daughter product, daughter isotope, radio-daughter, or daughter nuclide) is the remaining nuclide left over from radioactive decay. Radioactive decay often proceeds via a sequence of steps ( ...

of 4n+2

(the Radium or Uranium series) , Radium G , style="text-align:right" , 82 , style="text-align:right" , 124 , 205.9744653(13) , colspan="3" style="text-align:center;", Observationally StableExperimental lower bound is

\tau_ > 2.5\times10^

years; the theoretical lifetime for α decay to ²⁰²Hg is

> 10^

years. , 0+ , 0.241(1) , 0.2084–0.2748 , - , style="text-indent:1em" , ^206m1Pb , , colspan="3" style="text-indent:2em" , 2200.14(4) keV , 125(2) μs , , , 7− , , , - , style="text-indent:1em" , ^206m2Pb , , colspan="3" style="text-indent:2em" , 4027.3(7) keV , 202(3) ns , , , 12+ , , , - , ²⁰⁷PbFinal decay product of 4n+3 decay chain (the Actinium series) , Actinium D , style="text-align:right" , 82 , style="text-align:right" , 125 , 206.9758969(13) , colspan="3" style="text-align:center;", Observationally StableExperimental lower bound is

\tau_ > 1.9\times10^

years; the theoretical lifetime for α decay to ²⁰³Hg is

> 10^

years. , 1/2− , 0.221(1) , 0.1762–0.2365 , - , style="text-indent:1em" , ^207mPb , , colspan="3" style="text-indent:2em" , 1633.368(5) keV , 806(6) ms , IT , ²⁰⁷Pb , 13/2+ , , , - , ²⁰⁸PbFinal decay product of 4n decay chain (the

Thorium series In nuclear science, the decay chain refers to a series of radioactive decays of different radioactive decay products as a sequential series of transformations. It is also known as a "radioactive cascade". Most radioisotopes do not decay direct ...

) , Thorium D , style="text-align:right" , 82 , style="text-align:right" , 126 , 207.9766521(13) , colspan="3" style="text-align:center;", Observationally StableExperimental lower bound is

\tau_ > 2.6\times10^

years; the theoretical lifetime for α decay to ²⁰⁴Hg is

> 10^

years. , 0+ , 0.524(1) , 0.5128–0.5621 , - , style="text-indent:1em" , ^208mPb , , colspan="3" style="text-indent:2em" , 4895(2) keV , 500(10) ns , , , 10+ , , , - , ²⁰⁹Pb , , style="text-align:right" , 82 , style="text-align:right" , 127 , 208.9810901(19) , 3.253(14) h , β⁻ , ''²⁰⁹Bi'' , 9/2+ , TraceIntermediate decay product of ²³⁷Np , , - , rowspan=2, ²¹⁰Pb , rowspan=2, Radium D
Radiolead
Radio-lead , rowspan=2 style="text-align:right" , 82 , rowspan=2 style="text-align:right" , 128 , rowspan=2, 209.9841885(16) , rowspan=2, 22.20(22) y , β⁻ (100%) , ²¹⁰Bi , rowspan=2, 0+ , rowspan=2, TraceIntermediate

of ²³⁸U , rowspan=2, , - , α (1.9×10⁻⁶%) , ²⁰⁶Hg , - , style="text-indent:1em" , ^210mPb , , colspan="3" style="text-indent:2em" , 1278(5) keV , 201(17) ns , , , 8+ , , , - , ²¹¹Pb , Actinium B , style="text-align:right" , 82 , style="text-align:right" , 129 , 210.9887370(29) , 36.1(2) min , β⁻ , ²¹¹Bi , 9/2+ , TraceIntermediate

of ²³⁵U , , - , ²¹²Pb , Thorium B , style="text-align:right" , 82 , style="text-align:right" , 130 , 211.9918975(24) , 10.64(1) h , β⁻ , ²¹²Bi , 0+ , TraceIntermediate

of ²³²Th , , - , style="text-indent:1em" , ^212mPb , , colspan="3" style="text-indent:2em" , 1335(10) keV , 6.0(0.8) μs , IT , ²¹²Pb , (8+) , , , - , ²¹³Pb , , style="text-align:right" , 82 , style="text-align:right" , 131 , 212.996581(8) , 10.2(3) min , β⁻ , ²¹³Bi , (9/2+) , , , - , ²¹⁴Pb , Radium B , style="text-align:right" , 82 , style="text-align:right" , 132 , 213.9998054(26) , 26.8(9) min , β⁻ , ²¹⁴Bi , 0+ , Trace , , - , style="text-indent:1em" , ^214mPb , , colspan="3" style="text-indent:2em" , 1420(20) keV , 6.2(0.3) μs , IT , ²¹²Pb , 8+# , , , - , ²¹⁵Pb , , style="text-align:right" , 82 , style="text-align:right" , 133 , 215.004660(60) , 2.34(0.19) min , β⁻ , ²¹⁵Bi , 9/2+# , , , - , ²¹⁶Pb , , style="text-align:right" , 82 , style="text-align:right" , 134 , 216.008030(210)# , 1.65(0.2) min , β⁻ , ²¹⁶Bi , 0+ , , , - , style="text-indent:1em" , ^216mPb , , colspan="3" style="text-indent:2em" , 1514(20) keV , 400(40) ns , IT , ²¹⁶Pb , 8+# , , , - , ²¹⁷Pb , , style="text-align:right" , 82 , style="text-align:right" , 135 , 217.013140(320)# , 20(5) s , β⁻ , ²¹⁷Bi , 9/2+# , , , - , ²¹⁸Pb , , style="text-align:right" , 82 , style="text-align:right" , 136 , 218.016590(320)# , 15(7) s , β⁻ , ²¹⁸Bi , 0+ , ,

Lead-206

²⁰⁶Pb is the final step in the decay chain of ²³⁸U, the "radium series" or "uranium series". In a closed system, over time, a given mass of ²³⁸U will decay in a sequence of steps culminating in ²⁰⁶Pb. The production of intermediate products eventually reaches an equilibrium (though this takes a long time, as the half-life of ²³⁴U is 245,500 years). Once this stabilized system is reached, the ratio of ²³⁸U to ²⁰⁶Pb will steadily decrease, while the ratios of the other intermediate products to each other remain constant. Like most radioisotopes found in the radium series, ²⁰⁶Pb was initially named as a variation of radium, specifically radium G. It is the decay product of both ²¹⁰Po (historically called radium F) by

, and the much rarer ²⁰⁶Tl (radium E^II) by

beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...

. Lead-206 has been proposed for use in

fast breeder A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. Breeder reactors achieve this because their neutron economy is high enough to create more fissile fuel than they use, by irradiation of a fertile mat ...

nuclear fission reactor coolant over the use of natural lead mixture (which also includes other stable lead isotopes) as a mechanism to improve neutron economy and greatly suppress unwanted production of highly radioactive byproducts.

Lead-204, -207, and -208

²⁰⁴Pb is entirely

primordial Primordial may refer to: * Primordial era, an era after the Big Bang. See Chronology of the universe * Primordial sea (a.k.a. primordial ocean, ooze or soup). See Abiogenesis * Primordial nuclide, nuclides, a few radioactive, that formed before t ...

, and is thus useful for estimating the fraction of the other lead isotopes in a given sample that are also primordial, since the relative fractions of the various primordial lead isotopes is constant everywhere. Any excess lead-206, -207, and -208 is thus assumed to be radiogenic in origin, allowing various uranium and thorium dating schemes to be used to estimate the age of rocks (time since their formation) based on the relative abundance of lead-204 to other isotopes. ²⁰⁷Pb is the end of the actinium series from ²³⁵U. ²⁰⁸Pb is the end of the

from ²³²Th. While it only makes up approximately half of the composition of lead in most places on Earth, it can be found naturally enriched up to around 90% in thorium ores. ²⁰⁸Pb is the heaviest known stable nuclide and also the heaviest known doubly magic nucleus, as ''Z'' = 82 and ''N'' = 126 correspond to closed nuclear shells. As a consequence of this particularly stable configuration, its neutron capture cross section is very low (even lower than that of

deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1). The nucleus of a deuterium atom, called a deuteron, contains one proton and one ...

in the thermal spectrum), making it of interest for

lead-cooled fast reactor The lead-cooled fast reactor is a nuclear reactor design that features a fast neutron spectrum and molten lead or lead-bismuth eutectic coolant. Molten lead or lead-bismuth eutectic can be used as the primary coolant because especially lead, and ...

Lead-212

²¹²Pb-containing radiopharmaceuticals have been trialed as therapeutic agents for the experimental cancer treatment targeted alpha-particle therapy.

References

Isotope masses from: * Isotopic compositions and standard atomic masses from: * * Half-life, spin, and isomer data selected from the following sources. * * * {{Authority control Lead