Isotopes of lead

Isotopes of lead

Main isotopes of lead (₈₂Pb)

Iso­tope Decay abun­dance half-life (t1/2) mode pro­duct 202Pb syn 5.25(28)×104 y ε 202Tl 204Pb 1.4% stable 205Pb trace 1.73(7)×107 y ε 205Tl 206Pb 24.1% stable 207Pb 22.1% stable 208Pb 52.4% stable 209Pb trace 3.253(14) h β− 209Bi 210Pb trace 22.3(22) y β− 210Bi 211Pb trace 36.1(2) min β− 211Bi 212Pb trace 10.64(1) h β− 212Bi 214Pb trace 26.8(9) min β− 214Bi Isotopic abundances vary greatly by sample
Standard atomic weight Ar, standard(Pb)	207.2(1)[1]
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Lead (₈₂Pb) 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: the uranium series (or radium series), the actinium series, and the thorium series, respectively; a fourth decay chain, the neptunium series, terminates with the thallium 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 and uranium–lead dating).

The longest-lived radioisotopes are ²⁰⁵Pb with a half-life 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 22.3 years, is useful for studying the sedimentation chronology of environmental samples on time scales shorter than 100 years.^[2]

The relative abundances of the four stable isotopes are approximately 1.5%, 24%, 22%, and 52.5%, combining to give a standard atomic weight (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.) A total of 43 lead isotopes are now known, including very unstable synthetic species.

In its fully ionized state, the isotope ²⁰⁵Pb also becomes stable.^[3]

List of isotopes

Nuclide[4] [n 1]	Historic name	Z	N	Isotopic mass (Da)[5] [n 2][n 3]	Half-life	Decaymode [n 4]	Daughterisotope [n 5][n 6]	Spin and parity [n 7][n 8]	Natural abundance (mole fraction)
		Excitation energy[n 8]							Normal proportion	Range of variation
178Pb		82	96	178.003830(26)	0.23(15) ms	α	174Hg	0+
179Pb		82	97	179.00215(21)#	3.9(1.1) ms	α	175Hg	(9/2−)
180Pb		82	98	179.997918(22)	4.5(11) ms	α	176Hg	0+
181Pb		82	99	180.99662(10)	45(20) ms	α (98%)	177Hg	(9/2−)
						β+ (2%)	181Tl
182Pb		82	100	181.992672(15)	60(40) ms [55(+40−35) ms]	α (98%)	178Hg	0+
						β+ (2%)	182Tl
183Pb		82	101	182.99187(3)	535(30) ms	α (94%)	179Hg	(3/2−)
						β+ (6%)	183Tl
183mPb		94(8) keV			415(20) ms	α	179Hg	(13/2+)
						β+ (rare)	183Tl
184Pb		82	102	183.988142(15)	490(25) ms	α	180Hg	0+
						β+ (rare)	184Tl
185Pb		82	103	184.987610(17)	6.3(4) s	α	181Hg	3/2−
						β+ (rare)	185Tl
185mPb		60(40)# keV			4.07(15) s	α	181Hg	13/2+
						β+ (rare)	185Tl
186Pb		82	104	185.984239(12)	4.82(3) s	α (56%)	182Hg	0+
						β+ (44%)	186Tl
187Pb		82	105	186.983918(9)	15.2(3) s	β+	187Tl	(3/2−)
						α	183Hg
187mPb		11(11) keV			18.3(3) s	β+ (98%)	187Tl	(13/2+)
						α (2%)	183Hg
188Pb		82	106	187.980874(11)	25.5(1) s	β+ (91.5%)	188Tl	0+
						α (8.5%)	184Hg
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−)
189m1Pb		40(30)# keV			50.5(2.1) s	β+ (99.6%)	189Tl	13/2+
						α (.4%)	185Hg
189m2Pb		2475(30)# keV			26(5) μs			(10)+
190Pb		82	108	189.978082(13)	71(1) s	β+ (99.1%)	190Tl	0+
						α (.9%)	186Hg
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−)
						α (.013%)	187Hg
191mPb		20(50) keV			2.18(8) min	β+ (99.98%)	191Tl	13/2(+)
						α (.02%)	187Hg
192Pb		82	110	191.975785(14)	3.5(1) min	β+ (99.99%)	192Tl	0+
						α (.0061%)	188Hg
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+
						α (7.3×10−6%)	190Hg
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+
						α (3×10−5%)	192Hg
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+)
						β+ (7%)	199Tl
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	EC (99%)	201Tl	5/2−
						β+ (1%)
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)	5.25(28)×104 y	EC (99%)	202Tl	0+
						α (1%)	198Hg
202m1Pb		2169.83(7) keV			3.53(1) h	IT (90.5%)	202Pb	9−
						EC (9.5%)	202Tl
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 9]		82	122	203.9730436(13)	Observationally Stable[n 10]			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)	1.73(7)×107 y	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 9][n 11]	Radium G[n 12]	82	124	205.9744653(13)	Observationally Stable[n 13]			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 9][n 14]	Actinium D	82	125	206.9758969(13)	Observationally Stable[n 15]			1/2−	0.221(1)	0.1762–0.2365
207mPb		1633.368(5) keV			806(6) ms	IT	207Pb	13/2+
208Pb[n 16]	Thorium D	82	126	207.9766521(13)	Observationally Stable[n 17]			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+	Trace[n 18]
210Pb	Radium D Radiolead Radio-lead	82	128	209.9841885(16)	22.3(22) y	β− (100%)	210Bi	0+	Trace[n 19]
						α (1.9×10−6%)	206Hg
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 20]
212Pb	Thorium B	82	130	211.9918975(24)	10.64(1) h	β−	212Bi	0+	Trace[n 21]
212mPb		1335(10) keV			6.0(0.8) μs	IT	212Pb	(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 19]
214mPb		1420(20) keV			6.2(0.3) μs	IT	212Pb	8+#
215Pb		82	133	215.004660(60)	2.34(0.19) min	β−	215Bi	9/2+#
216Pb		82	134	216.008030(210)#	1.65(0.2) min	β−	216Bi	0+
216mPb		1514(20) keV			400(40) ns	IT	216Pb	8+#
217Pb		82	135	217.013140(320)#	20(5) s	β−	217Bi	9/2+#
218Pb		82	136	218.016590(320)#	15(7) s	β−	218Bi	0+

1. ^mPb – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. Modes of decay:

   EC:	Electron capture
   IT:	Isomeric transition

5. Bold italics symbol as daughter – Daughter product is nearly stable.
6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.
8. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
9. Used in lead–lead dating
10. Believed to undergo α decay to ²⁰⁰Hg with a half-life over 1.4×10²⁰ years
11. Final decay product of 4n+2 decay chain (the Radium or Uranium series)
12. Kuhn, W. (1929). "LXVIII. Scattering of thorium C″ γ-radiation by radium G and ordinary lead". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. 8 (52): 628. doi:10.1080/14786441108564923.
13. Believed to undergo α decay to ²⁰²Hg with a half-life over 2.5×10²¹ years
14. Final decay product of 4n+3 decay chain (the Actinium series)
15. Believed to undergo α decay to ²⁰³Hg with a half-life over 1.9×10²¹ years
16. Final decay product of 4n decay chain (the Thorium series)
17. Heaviest observationally stable nuclide, believed to undergo α decay to ²⁰⁴Hg with a half-life over 2.6×10²¹ years
18. Intermediate decay product of 237Np
19. Intermediate decay product of 238U
20. Intermediate decay product of 235U
21. Intermediate decay product of ²³²Th

Lead-206

See also: Decay chain

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 alpha decay, and the much rarer 206Tl (radium E^II) by beta decay.

Lead-206 has been proposed for use in fast breeder 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.^[6]

Lead-204, -207, and -208

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.^[7] Any excess lead-206, -207, and -208 is thus assumed to be radiogenic in origin,^[7] 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 thorium series 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.^{[8] 208}Pb is the heaviest known stable isotope of any element, and also the heaviest known doubly magic nucleus, as Z = 82 and N = 126 correspond to closed nuclear shells.^[9] As a consequence of this particularly stable configuration, its neutron capture cross section is very low (even lower than that of deuterium in the thermal spectrum), making it of interest for lead-cooled fast reactors.

References

1. Meija et al. 2016. sfn error: no target: CITEREFMeijaCoplenBerglundBrand2016 (help)
2. Jeter, Hewitt W. (March 2000). "Determining the Ages of Recent Sediments Using Measurements of Trace Radioactivity" (PDF). Terra et Aqua (78): 21–28. Retrieved October 23, 2019.
3. Takahashi, K; Boyd, R. N.; Mathews, G. J.; Yokoi, K. (October 1987). "Bound-state beta decay of highly ionized atoms". Physical Review C. 36 (4): 1522–1528. Bibcode:1987PhRvC..36.1522T. doi:10.1103/PhysRevC.36.1522. ISSN 0556-2813. OCLC 1639677. PMID 9954244. Retrieved 2016-11-20.
4. Half-life, decay mode, nuclear spin, and isotopic composition is sourced in:
   Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
5. Wang, M.; Audi, G.; Kondev, F. G.; Huang, W. J.; Naimi, S.; Xu, X. (2017). "The AME2016 atomic mass evaluation (II). Tables, graphs, and references" (PDF). Chinese Physics C. 41 (3): 030003-1–030003-442. doi:10.1088/1674-1137/41/3/030003.
6. Khorasanov, G. L.; Ivanov, A. P.; Blokhin, A. I. (2002). Polonium Issue in Fast Reactor Lead Coolants and One of the Ways of Its Solution. 10th International Conference on Nuclear Engineering. pp. 711–717. doi:10.1115/ICONE10-22330.
7. Woods, G.D. (November 2014). Lead isotope analysis: Removal of 204Hg isobaric interference from 204Pb using ICP-QQQ in MS/MS mode (PDF) (Report). Stockport, UK: Agilent Technologies.
8. A. Yu. Smirnov; V. D. Borisevich; A. Sulaberidze (July 2012). "Evaluation of specific cost of obtainment of lead-208 isotope by gas centrifuges using various raw materials". Theoretical Foundations of Chemical Engineering. 46 (4): 373–378. doi:10.1134/S0040579512040161. S2CID 98821122.
9. Blank, B.; Regan, P.H. (2000). "Magic and doubly-magic nuclei". Nuclear Physics News. 10 (4): 20–27. doi:10.1080/10506890109411553. S2CID 121966707.

Isotope masses from:

• Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (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

Isotopic compositions and standard atomic masses from:

• de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
• Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.

Half-life, spin, and isomer data selected from the following sources.

• Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (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
• National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
• Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.