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Isotopes of polonium

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Polonium (Po) has 33 isotopes, all of which are radioactive, with between 186 and 227 nucleons. 210Po with a half-life of 138.376 days has the longest half-life of naturally occurring polonium. 209Po with a half-life of 103 years has the longest half-life of all isotopes of polonium. 209Po and 208Po (half-life 2.9 years) can be made through the alpha, proton, or deuteron bombardment of lead or bismuth in a cyclotron.[citation needed]

Polonium-210

210Po is an alpha emitter that has a half-life of 138.376 days; it decays directly to its daughter isotope 206Pb. A milligram of 210Po emits as many alpha particles per second as 5 grams of 226Ra.[1] A few curies (1 curie equals 37 gigabecquerels) of 210Po emit a blue glow which is caused by excitation of surrounding air. A single gram of 210Po generates 140 watts of power.[2] Because it emits many alpha particles, which are stopped within a very short distance in dense media and release their energy, 210Po has been used as a lightweight heat source to power thermoelectric cells in artificial satellites; for instance, 210Po heat source was also used in each of the Lunokhod rovers deployed on the surface of the Moon, to keep their internal components warm during the lunar nights.[3] Some anti-static brushes contain up to 500 microcuries (19 MBq) of 210Po as a source of charged particles for neutralizing static electricity in materials like photographic film.[4] 210Po is also used in initiators for atomic bombs through the (α,n) reaction with beryllium.

The majority of the time 210Po decays by emission of an alpha particle only, not by emission of an alpha particle and a gamma ray. About one in 100,000 decays results in the emission of a gamma ray.[5] This low gamma ray production rate makes it more difficult to find and identify this isotope. Rather than gamma ray spectroscopy, alpha spectroscopy is the best method of measuring this isotope.

210Po occurs in minute amounts in nature, where it is an intermediate isotope in the radium series (also known as the uranium series) decay chain. It is generated via beta decay from 210Bi.

210Po is extremely toxic, with one microgram being enough to kill the average adult (250,000 times more toxic than hydrogen cyanide by weight). 210Po was used to kill Russian dissident and ex-FSB officer Alexander V. Litvinenko in 2006[6] and, following exhumation and analysis of his corpse, was in November 2013 suspected as a possible cause of Yasser Arafat's death.[7]

Table

Nuclide
symbol 		Historic
name 		Z(p)[8][9] N(n)[8][9]  
Isotopic mass (u)[10]
  		Half-life[10][11][12] Decay
mode(s)[13][n 1] 		Daughter
isotope(s)[n 2] 		Nuclear
spin[10][11][12] 		Representative
isotopic
composition
(mole fraction) 		Range of natural
variation
(mole fraction)
Excitation energy
188Po 84 104 187.999422(21) 430(180) µs
[0.40(+20-15) ms] 		0+
189Po 84 105 188.998481(24) 5(1) ms 3/2-#
190Po 84 106 189.995101(14) 2.46(5) ms α (99.9%) 186Pb 0+
β+ (.1%) 190Bi
191Po 84 107 190.994574(12) 22(1) ms α 187Pb 3/2-#
β+ (rare) 191Bi
191mPo 130(21) keV 93(3) ms (13/2+)
192Po 84 108 191.991335(13) 32.2(3) ms α (99%) 188Pb 0+
β+ (1%) 192Bi
192mPo 2600(500)# keV ~1 µs 12+#
193Po 84 109 192.99103(4) 420(40) ms
[370(+46-40) ms] 		α 189Pb 3/2-#
β+ (rare) 193Bi
193mPo 100(30)# keV 240(10) ms
[243(+11-10) ms] 		α 189Pb (13/2+)
β+ (rare) 193Bi
194Po 84 110 193.988186(13) 0.392(4) s α 190Pb 0+
β+ (rare) 194Bi
194mPo 2525(2) keV 15(2) µs (11-)
195Po 84 111 194.98811(4) 4.64(9) s α (75%) 191Pb 3/2-#
β+ (25%) 195Bi
195mPo 110(50) keV 1.92(2) s α (90%) 191Pb 13/2+#
β+ (10%) 195Bi
IT (.01%) 195Po
196Po 84 112 195.985535(14) 5.56(12) s α (94%) 192Pb 0+
β+ (6%) 196Bi
196mPo 2490.5(17) keV 850(90) ns (11-)
197Po 84 113 196.98566(5) 53.6(10) s β+ (54%) 197Bi (3/2-)
α (44%) 193Pb
197mPo 230(80)# keV 25.8(1) s α (84%) 193Pb (13/2+)
β+ (16%) 197Bi
IT (.01%) 197Po
198Po 84 114 197.983389(19) 1.77(3) min α (57%) 194Pb 0+
β+ (43%) 198Bi
198m1Po 2565.92(20) keV 200(20) ns 11-
198m2Po 2691.86(20) keV 750(50) ns 12+
199Po 84 115 198.983666(25) 5.48(16) min β+ (92.5%) 199Bi (3/2-)
α (7.5%) 195Pb
199mPo 312.0(28) keV 4.17(4) min β+ (73.5%) 199Bi 13/2+
α (24%) 195Pb
IT (2.5%) 199Po
200Po 84 116 199.981799(15) 11.5(1) min β+ (88.8%) 200Bi 0+
α (11.1%) 196Pb
201Po 84 117 200.982260(6) 15.3(2) min β+ (98.4%) 201Bi 3/2-
α (1.6%) 197Pb
201mPo 424.1(24) keV 8.9(2) min IT (56%) 201Po 13/2+
EC (41%) 201Bi
α (2.9%) 197Pb
202Po 84 118 201.980758(16) 44.7(5) min β+ (98%) 202Bi 0+
α (2%) 198Pb
202mPo 2626.7(7) keV >200 ns 11-
203Po 84 119 202.981420(28) 36.7(5) min β+ (99.89%) 203Bi 5/2-
α (.11%) 199Pb
203m1Po 641.49(17) keV 45(2) s IT (99.96%) 203Po 13/2+
α (.04%) 199Pb
203m2Po 2158.5(6) keV >200 ns
204Po 84 120 203.980318(12) 3.53(2) h β+ (99.33%) 204Bi 0+
α (.66%) 200Pb
205Po 84 121 204.981203(21) 1.66(2) h β+ (99.96%) 205Bi 5/2-
α (.04%) 201Pb
205m1Po 143.166(17) keV 310(60) ns 1/2-
205m2Po 880.30(4) keV 645 µs 13/2+
205m3Po 1461.21(21) keV 57.4(9) ms IT 205Po 19/2-
205m4Po 3087.2(4) keV 115(10) ns 29/2-
206Po 84 122 205.980481(9) 8.8(1) d β+ (94.55%) 206Bi 0+
α (5.45%) 202Pb
206m1Po 1585.85(11) keV 222(10) ns (8+)#
206m2Po 2262.22(14) keV 1.05(6) µs (9-)#
207Po 84 123 206.981593(7) 5.80(2) h β+ (99.97%) 207Bi 5/2-
α (.021%) 203Pb
207m1Po 68.573(14) keV 205(10) ns 1/2-
207m2Po 1115.073(16) keV 49(4) µs 13/2+
207m3Po 1383.15(6) keV 2.79(8) s IT 207Po 19/2-
208Po 84 124 207.9812457(19) 2.898(2) a α (99.99%) 204Pb 0+
β+ (.00277%) 208Bi
209Po 84 125 208.9824304(20) 102(5) a α (99.52%) 205Pb 1/2-
β+ (.48%) 209Bi
210Po Radium F 84 126 209.9828737(13) 138.376(2) d α 206Pb 0+ Trace[n 3]
210mPo 5057.61(4) keV 263(5) ns 16+
211Po Actinium C' 84 127 210.9866532(14) 0.516(3) s α 207Pb 9/2+ Trace[n 4]
211m1Po 1462(5) keV 25.2(6) s α (99.98%) 207Pb (25/2+)
IT (.016%) 211Po
211m2Po 2135.7(9) keV 243(21) ns (31/2-)
211m3Po 4873.3(17) keV 2.8(7) µs (43/2+)
212Po Thorium C' 84 128 211.9888680(13) 299(2) ns α 208Pb 0+ Trace[n 5]
212mPo 2911(12) keV 45.1(6) s α (99.93%) 208Pb (18+)
IT (.07%) 212Po
213Po 84 129 212.992857(3) 3.65(4) µs α 209Pb 9/2+
214Po Radium C' 84 130 213.9952014(16) 164.3(20) µs α 210Pb 0+ Trace[n 3]
215Po Actinium A 84 131 214.9994200(27) 1.781(4) ms α (99.99%) 211Pb 9/2+ Trace[n 4]
β- (2.3×10−4%) 215At
216Po Thorium A 84 132 216.0019150(24) 0.145(2) s α 212Pb 0+ Trace[n 5]
β-β- (rare) 216Rn
217Po 84 133 217.006335(7) 1.47(5) s α (95%) 213Pb 5/2+#
β- (5%) 217At
218Po Radium A 84 134 218.0089730(26) 3.10(1) min α (99.98%) 214Pb 0+ Trace[n 3]
β- (.02%) 218At
219Po 84 135 219.01374(39)# 2# min
[>300 ns] 		7/2+#
220Po 84 136 220.01660(39)# 40# s
[>300 ns] 		0+
  1. ^ Abbreviations:
    EC: Electron capture
    IT: Isomeric transition
  2. ^ Bold for stable isotopes, bold italics for nearly stable isotopes (half-life longer than the age of the universe)
  3. ^ a b c Intermediate decay product of Uranium-238
  4. ^ a b Intermediate decay product of Uranium-235
  5. ^ a b Intermediate decay product of Thorium-232

Notes

  • 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.
  • Half-life abbreviations are a=annum(year), d=day, min=minute, s=second, ms=millisecond, µs=microsecond, ns=nanosecond.
  • A superscripted m (or m2, etc.) refers to an isomer of that particular isotope.

References

  1. ^ http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/elements.pdf
  2. ^ Polonium, Argonne National Laboratory
  3. ^ Andrew Wilson, Solar System Log, (London: Jane's Publishing Company Ltd, 1987), p. 64.
  4. ^ Staticmaster
  5. ^ 210PO A DECAY
  6. ^ Cowell, Alan (November 24, 2006). "Radiation Poisoning Killed Ex-Russian Spy". The New York Times.
  7. ^ "Arafat's death: what is Polonium-210?". Al Jazeera. July 10, 2012.
  8. ^ a b 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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. ^ a b 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. {{cite journal}}: Unknown parameter |laysummary= ignored (help)
  10. ^ a b c G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. ^ a b National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005. {{cite web}}: Check date values in: |accessdate= (help)
  12. ^ a b N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide (ed.). CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. p. 11-50. ISBN 978-0-8493-0485-9.
  13. ^ http://www.nucleonica.net/unc.aspx
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