Isotopes of polonium

Main isotopes of Chemistry:polonium (84Po) | Iso­tope | Decay

|

| abun­dance | half-life (t1/2) | mode | pro­duct
208Po  | syn | 2.898 y  | α | 204Pb
β+ | 208Bi
209Po  | syn  | 125.2 y[1] | α  | 205Pb
β+ | 209Bi
210Po | trace | 138.376 d  | α  | 206Pb
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There are 42 known isotopes of polonium (84Po), all radioactive, stretching from 186Po to 227Po. The isotopes 210 through 218 occur naturally in the four principal decay chains; of these, 210Po with a half-life of 138.376 days has the longest half-life and is, therefore, the most abundant by mass. It is also the most easily synthesized isotope, by neutron capture on natural bismuth, and so by far the most abundant artificial isotope as well.

Two other isotopes have longer lives: 209Po with a half-life of 124 years and 208Po with a half-life of 2.898 years. Both are made by using a cyclotron to bombard bismuth with protons.[2]

## List of isotopes

Nuclide
[n 1] | Historic
name  | Z | N | Isotopic mass (u)
[n 2][n 3] | Half-life
| Decay
mode
| Daughter
isotope
[n 4][n 5] | Spin and
parity
[n 6][n 7] | Isotopic
abundance

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Excitation energy[n 7]
186Po  |  | 84  | 102  | 186.004403(20)  | 28+16
−6 μs
| α | 182Pb  | 0+  |
187Po  |  | 84  | 103  | 187.003030(40)  | 1.40(25) ms  | α  | 183Pb  | 1/2−, 5/2−  |
187mPo[n 8] |  | 4(27) keV  | 0.5 ms  | α  | 183Pb  | 13/2+#  |
188Po  |  | 84  | 104  | 187.999416(21)  | 270(30) μs  | α  | 184Pb  | 0+  |
189Po  |  | 84  | 105  | 188.998473(24)  | 3.5(5) ms  | α  | 185Pb  | (5/2−)  |
190Po  |  | 84  | 106  | 189.995102(14)  | 2.45(5) ms  | α  | 186Pb  | 0+  |
191Po  |  | 84  | 107  | 190.994558(8)  | 22(1) ms  | α  | 187Pb  | 3/2−  |
191mPo  |  | 61(11) keV  | 93(3) ms  | α  | 187mPb  | 13/2+  |
192Po  |  | 84  | 108  | 191.991340(11)  | 32.2(3) ms  | α  | 188Pb  | 0+  |
192mPo  |  | 2294.6(10) keV  | 580(100) ns  | IT  | 192Po  | 11−  |
193Po  |  | 84  | 109  | 192.991062(16)  | 399(34) ms  | α  | 189Pb  | 3/2−  |
193mPo  |  | 100(6) keV  | 245(11) ms  | α  | 189mPb  | 13/2+  |
194Po  |  | 84  | 110  | 193.988186(14)  | 392(4) ms  | α  | 190Pb  | 0+  |
194mPo  |  | 2313.4(3) keV  | 12.9(5) μs  | IT  | 194Po  | (10−)  |
195Po  |  | 84  | 111  | 194.988066(6)  | 4.64(9) s  | α (94%)  | 191Pb  | 3/2−  |
β+ (6%)  | 195Bi
195mPo  |  | 148(9) keV  | 1.92(2) s  | α  | 191mPb  | 13/2+  |
196Po  |  | 84  | 112  | 195.985541(6)  | 5.63(7) s  | α (94%)  | 192Pb  | 0+  |
β+ (6%)  | 196Bi
196mPo  |  | 2493.9(4) keV  | 856(17) ns  | IT  | 196Po  | 11−  |
197Po  |  | 84  | 113  | 196.985622(11)  | 53.6(9) s  | β+ (56%)  | 197Bi  | (3/2−)  |
α (44%)  | 193Pb
197mPo  |  | 196(12) keV  | 25.8(1) s  | α (84%)  | 193mPb  | 13/2+  |
β+ ?  | 197Bi
IT ?  | 197Po
198Po  |  | 84  | 114  | 197.983389(19)  | 1.760(24) min  | α (57%)  | 194Pb  | 0+  |
β+ (43%)  | 198Bi
198m1Po  |  | 2565.92(20) keV  | 200(20) ns  | IT  | 198Po  | 11−  |
198m2Po  |  | 2740(50)# keV  | 750(50) ns  | IT  | 198Po  | 12+  |
199Po  |  | 84  | 115  | 198.983640(6)  | 5.47(15) min  | β+ (92.5%)  | 199Bi  | 3/2−  |
α (7.5%)  | 195Pb
199mPo  |  | 311.7(27) keV  | 4.17(5) min  | β+ (73.5%)  | 199Bi  | 13/2+  |
α (24%)  | 195Pb
IT (2.5%)  | 199Po
200Po  |  | 84  | 116  | 199.981812(8)  | 11.51(8) min  | β+ (88.9%)  | 200Bi  | 0+  |
α (11.1%)  | 196Pb
200m1Po  |  | 2596.1(3) keV  | 100(10) ns  | IT  | 200Po  | 11-  |
200m2Po  |  | 2817(7) keV  | 268(3) ns  | IT  | 200Po  | 12+  |
201Po  |  | 84  | 117  | 200.982264(5)  | 15.6(1) min  | β+ (98.87%)  | 201Bi  | 3/2−  |
α (1.13%)  | 197Pb
201mPo  |  | 423.8(24) keV  | 8.96(12) min  | IT (56.2(12)%)  | 201Po  | 13/2+  |
β+ (41.4(7)%)  | 201Bi
α (2.4(5)%)  | 197Pb
202Po  |  | 84  | 118  | 201.980739(9)  | 44.6(4) min  | β+ (98.08%)  | 202Bi  | 0+  |
α (1.92%)  | 198Pb
202mPo  |  | 1712(12) keV  | 110(15) ns  | IT  | 202Po  | 8+  |
203Po  |  | 84  | 119  | 202.981416(5)  | 36.7(5) min  | β+ (99.89%)  | 203Bi  | 5/2−  |
α (0.11%)  | 199Pb
203m1Po  |  | 641.68(14) keV  | 45(2) s  | IT  | 203Po  | 13/2+  |
α ?  | 199Pb
203m2Po  |  | 2158.5(6) keV  | >200 ns  | IT  | 203Po  |  |
204Po  |  | 84  | 120  | 203.980310(11)  | 3.519(12) h  | β+ (99.33%)  | 204Bi  | 0+  |
α (0.67%)  | 200Pb
204mPo  |  | 1639.03(6) keV  | 158.6(18) ns  | IT  | 208Po  | 8+  |
205Po  |  | 84  | 121  | 204.981190(11)  | 1.74(8) h  | β+ (99.96%)  | 205Bi  | 5/2−  |
α (0.04%)  | 201Pb
205m1Po  |  | 143.166(15) keV  | 310(60) ns  | IT  | 205Po  | 1/2−  |
205m2Po  |  | 880.31(4) keV  | 645(20) μs  | IT  | 205Po  | 13/2+  |
205m3Po  |  | 1461.21(21) keV  | 57.4(9) ms  | IT  | 205Po  | 19/2−  |
205m4Po  |  | 3087.2(4) keV  | 115(10) ns  | IT  | 205Po  | 29/2−  |
206Po  |  | 84  | 122  | 205.980474(4)  | 8.8(1) d  | β+ (94.55%)  | 206Bi  | 0+  |
α (5.45%)  | 202Pb
206m1Po  |  | 1585.90(11) keV  | 232(4) ns  | IT  | 206Po  | 8+  |
206m2Po  |  | 2262.09(12) keV  | 1.05(6) μs  | IT  | 206Po  | 9−  |
207Po  |  | 84  | 123  | 206.981593(7)  | 5.80(2) h  | β+ (99.979%)  | 207Bi  | 5/2−  |
α (0.021%)  | 203Pb
207m1Po  |  | 68.557(14) keV  | 205(10) ns  | IT  | 207Po  | 1/2−  |
207m2Po  |  | 1115.076(17) keV  | 49(4) μs  | IT  | 207Po  | 13/2+  |
207m3Po  |  | 1383.16(7) keV  | 2.79(8) s  | IT  | 207Po  | 19/2−  |
208Po  |  | 84  | 124  | 207.9812460(18)  | 2.898(2) y  | α  | 204Pb | 0+  |
β+ (0.0042%)  | 208Bi
208mPo  |  | 1528.22(4) keV  | 373(8) ns  | IT  | 208Po  | 8+  |
209Po  |  | 84  | 125  | 208.9824304(19)  | 124(3) y  | α (99.546%)  | 205Pb  | 1/2−  |
β+ (0.454%)  | 209Bi
209mPo  |  | 4265.4(3) keV  | 119(4) ns  | IT  | 209Po  | 31/2−  |
210Po[n 9] | Radium F  | 84  | 126  | 209.9828737(12)  | 138.376(2) d  | α  | 206Pb | 0+  | Trace[n 10]
210m1Po  |  | 1556.97(3) keV  | 98.9(25) ns  | IT  | 210Po  | 8+  |
210m2Po  |  | 5057.65(5) keV  | 263(5) ns  | IT  | 210Po  | 16+  |
211Po  | Actinium C'  | 84  | 127  | 210.9866532(13)  | 516(3) ms  | α  | 207Pb | 9/2+  | Trace[n 11]
211m1Po  |  | 1462(5) keV  | 25.2(6) s  | α (99.984%)  | 207Pb | (25/2+)  |
IT (0.016%)  | 211Po
211m2Po  |  | 2135(5) keV  | 243(21) ns  | IT  | 211Po  | (31/2−)  |
211m3Po  |  | 4872(6) keV  | 2.8(7) μs  | IT  | 211Po  | (43/2+)  |
212Po  | Thorium C'  | 84  | 128  | 211.9888680(12)  | 294.4(8) ns  | α  | 208Pb | 0+  | Trace[n 12]
212mPo  |  | 2923(4) keV  | 45.1(6) s  | α (99.93%)  | 208Pb | (18+)  |
IT (0.07%)  | 212Po
213Po  |  | 84  | 129  | 212.992857(3)  | 3.705(1) μs  | α  | 209Pb  | 9/2+  | Trace[n 13]
214Po  | Radium C'  | 84  | 130  | 213.9952013(16)  | 163.47(3) μs  | α  | 210Pb  | 0+  | Trace[n 10]
215Po  | Actinium A  | 84  | 131  | 214.9994184(23)  | 1.781(5) ms  | α  | 211Pb  | 9/2+  | Trace[n 11]
β− (2.3×10−4%)  | 215At
216Po  | Thorium A  | 84  | 132  | 216.0019134(19)  | 143.7(5) ms[3] | α[n 14] | 212Pb  | 0+  | Trace[n 12]
217Po  |  | 84  | 133  | 217.006316(7)  | 1.53(5) s  | α (97.5%)  | 213Pb  | (9/2+)  | Trace[n 13]
β− (2.5%)  | 217At
218Po  | Radium A  | 84  | 134  | 218.0089712(21)  | 3.097(12) min  | α (99.98%)  | 214Pb  | 0+  | Trace[n 10]
β− (0.02%)  | 218At
219Po  |  | 84  | 135  | 219.013614(17)  | 10.3(10) min  | β− (71.8%)  | 219At  | 9/2+#  |
α (28.2%)  | 215Pb
220Po  |  | 84  | 136  | 220.016386(19)  | 10# s
[>300 ns]  | β− ?  | 220At  | 0+  |
221Po  |  | 84  | 137  | 221.021228(21)  | 2.2 +/- 0.7 min  | β− | 221At  | 9/2+#  |
222Po  |  | 84  | 138  | 222.02414(4)  | 9.1 +/- 7.2 min  | β− | 222At  | 0+  |
223Po  |  | 84  | 139  | 223.02907(21)#  | 6# s
[>300 ns]  | β− ?  | 223At  | 11/2+#  |
224Po  |  | 84  | 140  | 224.03211(21)#  | 3# min
[>300 ns]  | β− ?  | 224At  | 0+  |
225Po  |  | 84  | 141  | 225.03712(32)#  | 10# s
[>300 ns]  | β− ?  | 225At  | 3/2+#  |
226Po  |  | 84  | 142  | 226.04031(43)#  | 1# min
[>300 ns]  | β− ?  | 226At  | 0+  |
227Po  |  | 84  | 143  | 227.04539(43)#  | 2# s
[>300 ns]  | β− ?  | 227At  | 5/2+#  |

1. ↑ mPo - 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. ↑ Bold italics symbol as daughter - Daughter product is nearly stable.
5. ↑ Bold symbol as daughter - Daughter product is stable.
6. ↑ ( ) spin value - Indicates spin with weak assignment arguments.
7. ↑ 7.0 7.1 # - Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
8. ↑ Order of ground state and isomer is uncertain.
9. ↑ Most common isotope
10. ↑ 10.0 10.1 10.2 Intermediate decay product of 238U
11. ↑ 11.0 11.1 Intermediate decay product of 235U
12. ↑ 12.0 12.1 Intermediate decay product of 232Th
13. ↑ 13.0 13.1 Intermediate decay product of 237Np
14. ↑ Theoretically capable of β−β− decay to 216Rn

Daughter products other than polonium

* Isotopes of astatine
* Isotopes of bismuth
* Isotopes of lead

## References

1. ↑ Boutin, Chad. "Polonium's Most Stable Isotope Gets Revised Half-Life Measurement". NIST Tech Beat. http://www.nist.gov/pml/div682/po-090914.cfm. Retrieved 9 September 2014.
2. ↑ Carvalho, F.; Fernandes, S.; Fesenko, S.; Holm, E.; Howard, B.; Martin, P.; Phaneuf, P.; Porcelli, D. et al. (2017). The Environmental Behaviour of Polonium. Technical reports series. 484. Vienna: International Atomic Energy Agency. p. 22. ISBN 978-92-0-112116-5.
3. ↑ Li, ChenxiangExpression error: Unrecognized word "et". (2026). "Precise measurement of 216Po half-life with exact parent-daughter pairing in PandaX-4T". Physical Review C 113 (14610). doi:10.1103/6r8d-qxb8.

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