Isotopes of lead

Lead (Pb) has four stable isotopes: ²⁰⁴Pb, ²⁰⁶Pb, ²⁰⁷Pb, ²⁰⁸Pb. Lead-204 is entirely a primordial nuclide and is not a radiogenic nuclide. The three isotopes lead-206, lead-207, and lead-208 represent the ends of three decay chains called the uranium series (or radium series), the actinium series, and the thorium series, respectively. These series represent the decay chain products of long-lived primoridal U-238, U-235, and Th-232, respectively. However, each of them also occurs, to some extent, as primordial isotopes which 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 and uranium-lead dating).

The longest-lived radioisotopes are ²⁰⁵Pb with a half-life of ~15.3 million years and ²⁰²Pb with a half-life of ~53,000 years. Of naturally-occurring radioisotopes, the longest half-life is ²¹⁰Pb with a half-life of 22.20 years.

The standard atomic mass (abundance-weighted average of the stable isotopes) is 207.2(1) u. 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 1.9×10¹⁹ years). A total of 38 Pb isotopes are now known, including very unstable synthetic species.

1 Lead-206
2 Lead 207, 208, and 204
3 Table
- 3.1 Notes
4 References

Lead-206

Lighter: Lead-205	Isotopes of lead is an isotope of lead	Heavier: Lead-206
Decay product of: Polonium-210 (α) Thallium-206 (β-)	Decay chain of Isotopes of lead	Decays to: (stable)

Lead 207, 208, and 204

²⁰⁷Pb is the end of the Actinium series from ²³⁵U.

²⁰⁸Pb is the end of the Thorium series from ²³²Th.

²⁰⁴Pb is entirely primordial, 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).

Table

nuclide symbol	historic name	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)^[1]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	historic name	excitation energy			half-life	decay mode(s)^[1]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
¹⁷⁸Pb		82	96	178.003830(26)	0.23(15) ms			0+
¹⁷⁹Pb		82	97	179.00215(21)#	3# ms			5/2-#
¹⁸⁰Pb		82	98	179.997918(22)	4.5(11) ms			0+
¹⁸¹Pb		82	99	180.99662(10)	45(20) ms	α (98%)	¹⁷⁷Hg	5/2-#
¹⁸¹Pb		82	99	180.99662(10)	45(20) ms	β⁺ (2%)	¹⁸¹Tl	5/2-#
¹⁸²Pb		82	100	181.992672(15)	60(40) ms [55(+40-35) ms]	α (98%)	¹⁷⁸Hg	0+
¹⁸²Pb		82	100	181.992672(15)	60(40) ms [55(+40-35) ms]	β⁺ (2%)	¹⁸²Tl	0+
¹⁸³Pb		82	101	182.99187(3)	535(30) ms	α (94%)	¹⁷⁹Hg	(3/2-)
¹⁸³Pb		82	101	182.99187(3)	535(30) ms	β⁺ (6%)	¹⁸³Tl	(3/2-)
^183mPb		94(8) keV			415(20) ms	α	¹⁷⁹Hg	(13/2+)
^183mPb		94(8) keV			415(20) ms	β⁺ (rare)	¹⁸³Tl	(13/2+)
¹⁸⁴Pb		82	102	183.988142(15)	490(25) ms	α	¹⁸⁰Hg	0+
¹⁸⁴Pb		82	102	183.988142(15)	490(25) ms	β⁺ (rare)	¹⁸⁴Tl	0+
¹⁸⁵Pb		82	103	184.987610(17)	6.3(4) s	α	¹⁸¹Hg	3/2-
¹⁸⁵Pb		82	103	184.987610(17)	6.3(4) s	β⁺ (rare)	¹⁸⁵Tl	3/2-
^185mPb		60(40)# keV			4.07(15) s	α	¹⁸¹Hg	13/2+
^185mPb		60(40)# keV			4.07(15) s	β⁺ (rare)	¹⁸⁵Tl	13/2+
¹⁸⁶Pb		82	104	185.984239(12)	4.82(3) s	α (56%)	¹⁸²Hg	0+
¹⁸⁶Pb		82	104	185.984239(12)	4.82(3) s	β⁺ (44%)	¹⁸⁶Tl	0+
¹⁸⁷Pb		82	105	186.983918(9)	15.2(3) s	β⁺	¹⁸⁷Tl	(3/2-)
¹⁸⁷Pb		82	105	186.983918(9)	15.2(3) s	α	¹⁸³Hg	(3/2-)
^187mPb		11(11) keV			18.3(3) s	β⁺ (98%)	¹⁸⁷Tl	(13/2+)
^187mPb		11(11) keV			18.3(3) s	α (2%)	¹⁸³Hg	(13/2+)
¹⁸⁸Pb		82	106	187.980874(11)	25.5(1) s	β⁺ (91.5%)	¹⁸⁸Tl	0+
¹⁸⁸Pb		82	106	187.980874(11)	25.5(1) s	α (8.5%)	¹⁸⁴Hg	0+
^188m1Pb		2578.2(7) keV			830(210) ns			(8-)
^188m2Pb		2800(50) keV			797(21) ns
¹⁸⁹Pb		82	107	188.98081(4)	51(3) s	β⁺	¹⁸⁹Tl	(3/2-)
^189mPb		40(30)# keV			1# min	β⁺ (99.6%)	¹⁸⁹Tl	(13/2+)
^189mPb		40(30)# keV			1# min	α (.4%)	¹⁸⁵Hg	(13/2+)
¹⁹⁰Pb		82	108	189.978082(13)	71(1) s	β⁺ (99.1%)	¹⁹⁰Tl	0+
¹⁹⁰Pb		82	108	189.978082(13)	71(1) s	α (.9%)	¹⁸⁶Hg	0+
^190m1Pb		2614.8(8) keV			150 ns			(10)+
^190m2Pb		2618(20) keV			25 µs			(12+)
^190m3Pb		2658.2(8) keV			7.2(6) µs			(11)-
¹⁹¹Pb		82	109	190.97827(4)	1.33(8) min	β⁺ (99.987%)	¹⁹¹Tl	(3/2-)
¹⁹¹Pb		82	109	190.97827(4)	1.33(8) min	α (.013%)	¹⁸⁷Hg	(3/2-)
^191mPb		20(50) keV			2.18(8) min	β⁺ (99.98%)	¹⁹¹Tl	13/2(+)
^191mPb		20(50) keV			2.18(8) min	α (.02%)	¹⁸⁷Hg	13/2(+)
¹⁹²Pb		82	110	191.975785(14)	3.5(1) min	β⁺ (99.99%)	¹⁹²Tl	0+
¹⁹²Pb		82	110	191.975785(14)	3.5(1) min	α (.0061%)	¹⁸⁸Hg	0+
^192m1Pb		2581.1(1) keV			164(7) ns			(10)+
^192m2Pb		2625.1(11) keV			1.1(5) µs			(12+)
^192m3Pb		2743.5(4) keV			756(21) ns			(11)-
¹⁹³Pb		82	111	192.97617(5)	5# min	β⁺	¹⁹³Tl	(3/2-)
^193m1Pb		130(80)# keV			5.8(2) min	β⁺	¹⁹³Tl	13/2(+)
^193m2Pb		2612.5(5)+X keV			135(+25-15) ns			(33/2+)
¹⁹⁴Pb		82	112	193.974012(19)	12.0(5) min	β⁺ (100%)	¹⁹⁴Tl	0+
¹⁹⁴Pb		82	112	193.974012(19)	12.0(5) min	α (7.3×10⁻⁶%)	¹⁹⁰Hg	0+
¹⁹⁵Pb		82	113	194.974542(25)	~15 min	β⁺	¹⁹⁵Tl	3/2#-
^195m1Pb		202.9(7) keV			15.0(12) min	β⁺	¹⁹⁵Tl	13/2+
^195m2Pb		1759.0(7) keV			10.0(7) µs			21/2-
¹⁹⁶Pb		82	114	195.972774(15)	37(3) min	β⁺	¹⁹⁶Tl	0+
¹⁹⁶Pb		82	114	195.972774(15)	37(3) min	α (3×10⁻⁵%)	¹⁹²Hg	0+
^196m1Pb		1049.20(9) keV			<100 ns			2+
^196m2Pb		1738.27(12) keV			<1 µs			4+
^196m3Pb		1797.51(14) keV			140(14) ns			5-
^196m4Pb		2693.5(5) keV			270(4) ns			(12+)
¹⁹⁷Pb		82	115	196.973431(6)	8.1(17) min	β⁺	¹⁹⁷Tl	3/2-
^197m1Pb		319.31(11) keV			42.9(9) min	β⁺ (81%)	¹⁹⁷Tl	13/2+
						IT (19%)	¹⁹⁷Pb
						α (3×10⁻⁴%)	¹⁹³Hg
^197m2Pb		1914.10(25) keV			1.15(20) µs			21/2-
¹⁹⁸Pb		82	116	197.972034(16)	2.4(1) h	β⁺	¹⁹⁸Tl	0+
^198m1Pb		2141.4(4) keV			4.19(10) µs			(7)-
^198m2Pb		2231.4(5) keV			137(10) ns			(9)-
^198m3Pb		2820.5(7) keV			212(4) ns			(12)+
¹⁹⁹Pb		82	117	198.972917(28)	90(10) min	β⁺	¹⁹⁹Tl	3/2-
^199m1Pb		429.5(27) keV			12.2(3) min	IT (93%)	¹⁹⁹Pb	(13/2+)
^199m1Pb		429.5(27) keV			12.2(3) min	β⁺ (7%)	¹⁹⁹Tl	(13/2+)
^199m2Pb		2563.8(27) keV			10.1(2) µs			(29/2-)
²⁰⁰Pb		82	118	199.971827(12)	21.5(4) h	β⁺	²⁰⁰Tl	0+
²⁰¹Pb		82	119	200.972885(24)	9.33(3) h	IT (99%)	²⁰¹Pb	5/2-
²⁰¹Pb		82	119	200.972885(24)	9.33(3) h	β⁺ (1%)	²⁰¹Tl	5/2-
^201m1Pb		629.14(17) keV			61(2) s			13/2+
^201m2Pb		2718.5+X keV			508(5) ns			(29/2-)
²⁰²Pb		82	120	201.972159(9)	52.5(28)×10³ a	EC (99%)	²⁰²Tl	0+
²⁰²Pb		82	120	201.972159(9)	52.5(28)×10³ a	α (1%)	¹⁹⁸Hg	0+
^202m1Pb		2169.83(7) keV			3.53(1) h	IT (90.5%)	²⁰²Pb	9-
^202m1Pb		2169.83(7) keV			3.53(1) h	EC (9.5%)	²⁰²Tl	9-
^202m2Pb		4142.9(11) keV			110(5) ns			(16+)
^202m3Pb		5345.9(13) keV			107(5) ns			(19-)
²⁰³Pb		82	121	202.973391(7)	51.873(9) h	EC	²⁰³Tl	5/2-
^203m1Pb		825.20(9) keV			6.21(8) s	IT	²⁰³Pb	13/2+
^203m2Pb		2949.47(22) keV			480(7) ms			29/2-
^203m3Pb		2923.4+X keV			122(4) ns			(25/2-)
²⁰⁴Pb^{[n 3]}		82	122	203.9730436(13)	Observationally Stable^{[n 4]}			0+	0.014(1)	0.0104-0.0165
^204m1Pb		1274.00(4) keV			265(10) ns			4+
^204m2Pb		2185.79(5) keV			67.2(3) min			9-
^204m3Pb		2264.33(4) keV			0.45(+10-3) µs			7-
²⁰⁵Pb		82	123	204.9744818(13)	15.3(7)×10⁶ a	EC	²⁰⁵Tl	5/2-
^205m1Pb		2.329(7) keV			24.2(4) µs			1/2-
^205m2Pb		1013.839(13) keV			5.55(2) ms			13/2+
^205m3Pb		3195.7(5) keV			217(5) ns			25/2-
²⁰⁶Pb^{[n 3]}^{[n 5]}	Radium G	82	124	205.9744653(13)	Observationally Stable^{[n 6]}			0+	0.241(1)	0.2084-0.2748
^206m1Pb		2200.14(4) keV			125(2) µs			7-
^206m2Pb		4027.3(7) keV			202(3) ns			12+
²⁰⁷Pb^{[n 3]}^{[n 7]}	Actinium D	82	125	206.9758969(13)	Observationally Stable^{[n 8]}			1/2-	0.221(1)	0.1762-0.2365
^207mPb		1633.368(5) keV			806(6) ms	IT	²⁰⁷Pb	13/2+
²⁰⁸Pb^{[n 9]}	Thorium D	82	126	207.9766521(13)	Observationally Stable^{[n 10]}			0+	0.524(1)	0.5128-0.5621
^208mPb		4895(2) keV			500(10) ns			10+
²⁰⁹Pb		82	127	208.9810901(19)	3.253(14) h	β^-	²⁰⁹Bi	9/2+
²¹⁰Pb	Radium D Radiolead Radio-lead	82	128	209.9841885(16)	22.20(22) a	β^- (100%)	²¹⁰Bi	0+	Trace^{[n 11]}
²¹⁰Pb	Radium D Radiolead Radio-lead	82	128	209.9841885(16)	22.20(22) a	α (1.9×10⁻⁶%)	²⁰⁶Hg	0+	Trace^{[n 11]}
^210mPb		1278(5) keV			201(17) ns			8+
²¹¹Pb	Actinium B	82	129	210.9887370(29)	36.1(2) min	β^-	²¹¹Bi	9/2+	Trace^{[n 12]}
²¹²Pb	Thorium B	82	130	211.9918975(24)	10.64(1) h	β^-	²¹²Bi	0+	Trace^{[n 13]}
^212mPb		1335(10) keV			5(1) µs			(8+)
²¹³Pb		82	131	212.996581(8)	10.2(3) min	β^-	²¹³Bi	(9/2+)
²¹⁴Pb	Radium B	82	132	213.9998054(26)	26.8(9) min	β^-	²¹⁴Bi	0+	Trace^{[n 11]}
²¹⁵Pb		82	133	215.00481(44)#	36(1) s			5/2+#

^ Abbreviations:
EC: Electron capture
IT: Isomeric transition
^ Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)
^ ^a ^b ^c Used in lead-lead dating
^ Believed to undergo α decay to ²⁰⁰Hg with a half-life over 140×10¹⁵ years
^ Final decay product of 4n+2 decay chain (the Radium or Uranium series)
^ Believed to undergo α decay to ²⁰²Hg
^ Final decay product of 4n+3 decay chain (the Actinium series)
^ Believed to undergo α decay to ²⁰³Hg ({citation needed}}
^ Final decay product of 4n decay chain (the Thorium series)
^ Heaviest observationally stable nuclide, believed to undergo α decay to ²⁰⁴Hg with a half-life over 2×10¹⁹ years
^ ^a ^b Intermediate decay product of ²³⁸U
^ Intermediate decay product of ²³⁵U
^ Intermediate decay product of ²³²Th

Notes

Evaluated isotopic composition is for most but not all commercial samples.
The precision of the isotope abundances and atomic mass is limited through variations. The given ranges should be applicable to any normal terrestrial material.
Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References

^ http://www.nucleonica.net/unc.aspx

Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". Nuclear Physics A 729: 3–128. Bibcode 2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683. http://www.iupac.org/publications/pac/75/6/0683/pdf/.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. http://iupac.org/publications/pac/78/11/2051/pdf/. Lay summary.
Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". Nuclear Physics A 729: 3–128. Bibcode 2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/. Retrieved September 2005.
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0849304859.

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