# Isotopes of polonium

There are 42 isotopes of polonium ($_{84}$Po). They range in size from 186 to 227 nucleons. They are all radioactive. $^{210}$Po with a half-life of 138.376 days has the longest half-life of any naturally-occurring isotope of polonium and is the most common isotope of polonium. It is also the most easily synthesized polonium isotope. $^{209}$Po, which does not occur naturally, has the longest half-life of all isotopes of polonium at 124 years. $^{209}$Po can be made by using a cyclotron to bombard bismuth with protons, as can $^{208}$Po.

## List of isotopes

| Nuclide | Historic name | Z | N | Isotopic mass (Da) | Half-life | Decay mode | Daughter isotope | Spin and parity | Isotopic abundance |
| Isotopic abundance |||
| $^{186}$Po | | 84 | 102 | 186.004403(20) | 28+16 −6 μs | α | $^{182}$Pb | 0+ | |
| $^{187}$Po | | 84 | 103 | 187.003030(40) | 1.40(25) ms | α | $^{183}$Pb | 1/2−, 5/2− | |
| $^{187m}$Po | | 4(27) keV | 4(27) keV | 4(27) keV | 0.5 ms | α | $^{183}$Pb | 13/2+# | |
| $^{188}$Po | | 84 | 104 | 187.999416(21) | 270(30) μs | α | $^{184}$Pb | 0+ | |
| $^{189}$Po | | 84 | 105 | 188.998473(24) | 3.5(5) ms | α | $^{185}$Pb | (5/2−) | |
| $^{190}$Po | | 84 | 106 | 189.995102(14) | 2.45(5) ms | α | $^{186}$Pb | 0+ | |
| $^{191}$Po | | 84 | 107 | 190.994558(8) | 22(1) ms | α | $^{187}$Pb | 3/2− | |
| $^{191m}$Po | | 61(11) keV | 61(11) keV | 61(11) keV | 93(3) ms | α | $^{187m}$Pb | 13/2+ | |
| $^{192}$Po | | 84 | 108 | 191.991340(11) | 32.2(3) ms | α | $^{188}$Pb | 0+ | |
| $^{192m}$Po | | 2294.6(10) keV | 2294.6(10) keV | 2294.6(10) keV | 580(100) ns | IT | $^{192}$Po | 11− | |
| $^{193}$Po | | 84 | 109 | 192.991062(16) | 399(34) ms | α | $^{189}$Pb | 3/2− | |
| $^{193m}$Po | | 100(6) keV | 100(6) keV | 100(6) keV | 245(11) ms | α | $^{189m}$Pb | 13/2+ | |
| $^{194}$Po | | 84 | 110 | 193.988186(14) | 392(4) ms | α | $^{190}$Pb | 0+ | |
| $^{194m}$Po | | 2313.4(3) keV | 2313.4(3) keV | 2313.4(3) keV | 12.9(5) μs | IT | $^{194}$Po | (10−) | |
| $^{195}$Po | | 84 | 111 | 194.988066(6) | 4.64(9) s | α (94%) | $^{191}$Pb | 3/2− | |
| $^{195}$Po | | 84 | 111 | 194.988066(6) | 4.64(9) s | β$^+$? | $^{195}$Bi | 3/2− | |
| $^{195m}$Po | | 148(9) keV | 148(9) keV | 148(9) keV | 1.92(2) s | α | $^{191m}$Pb | 13/2+ | |
| $^{196}$Po | | 84 | 112 | 195.985541(6) | 5.56(12) s | α (94%) | $^{192}$Pb | 0+ | |
| $^{196}$Po | | 84 | 112 | 195.985541(6) | 5.56(12) s | β$^+$? | $^{196}$Bi | 0+ | |
| $^{196m}$Po | | 2493.9(4) keV | 2493.9(4) keV | 2493.9(4) keV | 856(17) ns | IT | $^{196}$Po | 11− | |
| $^{197}$Po | | 84 | 113 | 196.985622(11) | 53.6(9) s | β$^+$? | $^{197}$Bi | (3/2−) | |
| $^{197}$Po | | 84 | 113 | 196.985622(11) | 53.6(9) s | α (44%) | $^{193}$Pb | (3/2−) | |
| $^{197m}$Po | | 196(12)# keV | 196(12)# keV | 196(12)# keV | 25.8(1) s | α (84%) | $^{193m}$Pb | 13/2+ | |
| $^{197m}$Po | | 196(12)# keV | 196(12)# keV | 196(12)# keV | 25.8(1) s | β$^+$? | $^{197}$Bi | 13/2+ | |
| $^{197m}$Po | | 196(12)# keV | 196(12)# keV | 196(12)# keV | 25.8(1) s | IT? | $^{197}$Po | 13/2+ | |
| $^{198}$Po | | 84 | 114 | 197.983389(19) | 1.760(24) min | α (57%) | $^{194}$Pb | 0+ | |
| $^{198}$Po | | 84 | 114 | 197.983389(19) | 1.760(24) min | β$^+$ (43%) | $^{198}$Bi | 0+ | |
| $^{198m1}$Po | | 2565.92(20) keV | 2565.92(20) keV | 2565.92(20) keV | 200(20) ns | IT | $^{198}$Po | 11− | |
| $^{198m2}$Po | | 2740(50)# keV | 2740(50)# keV | 2740(50)# keV | 750(50) ns | IT | $^{198}$Po | 12+ | |
| $^{199}$Po | | 84 | 115 | 198.983666(25) | 5.48(16) min | β$^+$ (92.5%) | $^{199}$Bi | (3/2−) | |
| $^{199}$Po | | 84 | 115 | 198.983666(25) | 5.48(16) min | α (7.5%) | $^{195}$Pb | (3/2−) | |
| $^{199m}$Po | | 312.0(28) keV | 312.0(28) keV | 312.0(28) keV | 4.17(4) min | β$^+$ (73.5%) | $^{199}$Bi | 13/2+ | |
| $^{199m}$Po | | 312.0(28) keV | 312.0(28) keV | 312.0(28) keV | 4.17(4) min | α (24%) | $^{195}$Pb | 13/2+ | |
| $^{199m}$Po | | 312.0(28) keV | 312.0(28) keV | 312.0(28) keV | 4.17(4) min | IT (2.5%) | $^{199}$Po | 13/2+ | |
| $^{200}$Po | | 84 | 116 | 199.981799(15) | 11.5(1) min | β$^+$ (88.8%) | $^{200}$Bi | 0+ | |
| $^{200}$Po | | 84 | 116 | 199.981799(15) | 11.5(1) min | α (11.1%) | $^{196}$Pb | 0+ | |
| $^{201}$Po | | 84 | 117 | 200.982260(6) | 15.3(2) min | β$^+$ (98.4%) | $^{201}$Bi | 3/2− | |
| $^{201}$Po | | 84 | 117 | 200.982260(6) | 15.3(2) min | α (1.6%) | $^{197}$Pb | 3/2− | |
| $^{201m}$Po | | 424.1(24) keV | 424.1(24) keV | 424.1(24) keV | 8.9(2) min | IT (56.2(12)%) | $^{201}$Po | 13/2+ | |
| $^{201m}$Po | | 424.1(24) keV | 424.1(24) keV | 424.1(24) keV | 8.9(2) min | β$^+$ (41.4(7)%) | $^{201}$Bi | 13/2+ | |
| $^{201m}$Po | | 424.1(24) keV | 424.1(24) keV | 424.1(24) keV | 8.9(2) min | α (2.4(5)%) | $^{197}$Pb | 13/2+ | |
| $^{202}$Po | | 84 | 118 | 201.980758(16) | 44.7(5) min | β$^+$ (98%) | $^{202}$Bi | 0+ | |
| $^{202}$Po | | 84 | 118 | 201.980758(16) | 44.7(5) min | α (2%) | $^{198}$Pb | 0+ | |
| $^{202m}$Po | | 2626.7(7) keV | 2626.7(7) keV | 2626.7(7) keV | >200 ns | | | 11− | |
| $^{203}$Po | | 84 | 119 | 202.981420(28) | 36.7(5) min | β$^+$ (99.89%) | $^{203}$Bi | 5/2− | |
| $^{203}$Po | | 84 | 119 | 202.981420(28) | 36.7(5) min | α (.11%) | $^{199}$Pb | 5/2− | |
| $^{203m1}$Po | | 641.49(17) keV | 641.49(17) keV | 641.49(17) keV | 45(2) s | IT (99.96%) | $^{203}$Po | 13/2+ | |
| $^{203m1}$Po | | 641.49(17) keV | 641.49(17) keV | 641.49(17) keV | 45(2) s | α (.04%) | $^{199}$Pb | 13/2+ | |
| $^{203m2}$Po | | 2158.5(6) keV | 2158.5(6) keV | 2158.5(6) keV | >200 ns | | | | |
| $^{204}$Po | | 84 | 120 | 203.980318(12) | 3.53(2) h | β$^+$ (99.33%) | $^{204}$Bi | 0+ | |
| $^{204}$Po | | 84 | 120 | 203.980318(12) | 3.53(2) h | α (.66%) | $^{200}$Pb | 0+ | |
| $^{205}$Po | | 84 | 121 | 204.981203(21) | 1.66(2) h | β$^+$ (99.96%) | $^{205}$Bi | 5/2− | |
| $^{205}$Po | | 84 | 121 | 204.981203(21) | 1.66(2) h | α (.04%) | $^{201}$Pb | 5/2− | |
| $^{205m1}$Po | | 143.166(17) keV | 143.166(17) keV | 143.166(17) keV | 310(60) ns | | | 1/2− | |
| $^{205m2}$Po | | 880.30(4) keV | 880.30(4) keV | 880.30(4) keV | 645 μs | | | 13/2+ | |
| $^{205m3}$Po | | 1461.21(21) keV | 1461.21(21) keV | 1461.21(21) keV | 57.4(9) ms | IT | $^{205}$Po | 19/2− | |
| $^{205m4}$Po | | 3087.2(4) keV | 3087.2(4) keV | 3087.2(4) keV | 115(10) ns | | | 29/2− | |
| $^{206}$Po | | 84 | 122 | 205.980481(9) | 8.8(1) d | β$^+$ (94.55%) | $^{206}$Bi | 0+ | |
| $^{206}$Po | | 84 | 122 | 205.980481(9) | 8.8(1) d | α (5.45%) | $^{202}$Pb | 0+ | |
| $^{206m1}$Po | | 1585.85(11) keV | 1585.85(11) keV | 1585.85(11) keV | 222(10) ns | | | (8+)# | |
| $^{206m2}$Po | | 2262.22(14) keV | 2262.22(14) keV | 2262.22(14) keV | 1.05(6) μs | | | (9−)# | |
| $^{207}$Po | | 84 | 123 | 206.981593(7) | 5.80(2) h | β$^+$ (99.97%) | $^{207}$Bi | 5/2− | |
| $^{207}$Po | | 84 | 123 | 206.981593(7) | 5.80(2) h | α (.021%) | $^{203}$Pb | 5/2− | |
| $^{207m1}$Po | | 68.573(14) keV | 68.573(14) keV | 68.573(14) keV | 205(10) ns | | | 1/2− | |
| $^{207m2}$Po | | 1115.073(16) keV | 1115.073(16) keV | 1115.073(16) keV | 49(4) μs | | | 13/2+ | |
| $^{207m3}$Po | | 1383.15(6) keV | 1383.15(6) keV | 1383.15(6) keV | 2.79(8) s | IT | $^{207}$Po | 19/2− | |
| $^{208}$Po | | 84 | 124 | 207.9812457(19) | 2.898(2) y | α (99.99%) | $^{204}$Pb | 0+ | |
| $^{208}$Po | | 84 | 124 | 207.9812457(19) | 2.898(2) y | β$^+$ (.00277%) | $^{208}$Bi | 0+ | |
| $^{209}$Po | | 84 | 125 | 208.9824304(20) | 124(3) y | α (99.546%) | $^{205}$Pb | 1/2− | |
| $^{209}$Po | | 84 | 125 | 208.9824304(20) | 124(3) y | β$^+$ (.454%) | $^{209}$Bi | 1/2− | |
| $^{210}$Po | Radium F | 84 | 126 | 209.9828737(13) | 138.376(2) d | α | $^{206}$Pb | 0+ | Trace |
| $^{210m}$Po | | 5057.61(4) keV | 5057.61(4) keV | 5057.61(4) keV | 263(5) ns | | | 16+ | |
| $^{211}$Po | Actinium C' | 84 | 127 | 210.9866532(14) | 516(3) ms | α | $^{207}$Pb | 9/2+ | Trace |
| $^{211m1}$Po | | 1462(5) keV | 1462(5) keV | 1462(5) keV | 25.2(6) s | α (99.98%) | $^{207}$Pb | (25/2+) | |
| $^{211m1}$Po | | 1462(5) keV | 1462(5) keV | 1462(5) keV | 25.2(6) s | IT (.016%) | $^{211}$Po | (25/2+) | |
| $^{211m2}$Po | | 2135.7(9) keV | 2135.7(9) keV | 2135.7(9) keV | 243(21) ns | | | (31/2−) | |
| $^{211m3}$Po | | 4873.3(17) keV | 4873.3(17) keV | 4873.3(17) keV | 2.8(7) μs | | | (43/2+) | |
| $^{212}$Po | Thorium C' | 84 | 128 | 211.9888680(13) | 294.4(8) ns | α | $^{208}$Pb | 0+ | Trace |
| $^{212m}$Po | | 2911(12) keV | 2911(12) keV | 2911(12) keV | 45.1(6) s | α (99.93%) | $^{208}$Pb | (18+) | |
| $^{212m}$Po | | 2911(12) keV | 2911(12) keV | 2911(12) keV | 45.1(6) s | IT (.07%) | $^{212}$Po | (18+) | |
| $^{213}$Po | | 84 | 129 | 212.992857(3) | 3.65(4) μs | α | $^{209}$Pb | 9/2+ | Trace |
| $^{214}$Po | Radium C' | 84 | 130 | 213.9952014(16) | 164.3(20) μs | α | $^{210}$Pb | 0+ | Trace |
| $^{215}$Po | Actinium A | 84 | 131 | 214.9994200(27) | 1.781(4) ms | α | $^{211}$Pb | 9/2+ | Trace |
| $^{215}$Po | Actinium A | 84 | 131 | 214.9994200(27) | 1.781(4) ms | β$^−$ (2.3×10$^{−4}$%) | $^{215}$At | 9/2+ | Trace |
| $^{216}$Po | Thorium A | 84 | 132 | 216.0019150(24) | 145(2) ms | α | $^{212}$Pb | 0+ | Trace |
| $^{217}$Po | | 84 | 133 | 217.006335(7) | 1.47(5) s | α (95%) | $^{213}$Pb | 5/2+# | Trace |
| $^{217}$Po | | 84 | 133 | 217.006335(7) | 1.47(5) s | β$^−$ (5%) | $^{217}$At | 5/2+# | Trace |
| $^{218}$Po | Radium A | 84 | 134 | 218.0089730(26) | 3.10(1) min | α (99.98%) | $^{214}$Pb | 0+ | Trace |
| $^{218}$Po | Radium A | 84 | 134 | 218.0089730(26) | 3.10(1) min | β$^−$ (.02%) | $^{218}$At | 0+ | Trace |
| $^{219}$Po | | 84 | 135 | 219.01361(16) | 10.3(1) min | β$^−$ (71.8%) | $^{219}$At | 9/2+# | |
| $^{219}$Po | | 84 | 135 | 219.01361(16) | 10.3(1) min | α (28.2%) | $^{215}$Pb | 9/2+# | |
| $^{220}$Po | | 84 | 136 | 220.0164(18) | 40# s [>300 ns] | β$^−$ | $^{220}$At | 0+ | |
| $^{221}$Po | | 84 | 137 | 221.02123(20) | 2.2(0.7) min | β$^−$ | $^{221}$At | 9/2+# | |
| $^{222}$Po | | 84 | 138 | 222.024144(40) | 9.1(7.2) min | β$^−$ | $^{222}$At | 0+ | |
| $^{223}$Po | | 84 | 139 | 223.02907(21)# | 6# s [>300 ns] | β$^−$? | $^{223}$At | 11/2+# | |
| $^{224}$Po | | 84 | 140 | 224.03211(21)# | 3# min [>300 ns] | β$^−$? | $^{224}$At | 0+ | |
| $^{225}$Po | | 84 | 141 | 225.03712(32)# | 10# s [>300 ns] | β$^−$? | $^{225}$At | 3/2+# | |
| $^{226}$Po | | 84 | 142 | 226.04031(43)# | 1# min [>300 ns] | β$^−$? | $^{226}$At | 0+ | |
| $^{227}$Po | | 84 | 143 | 227.04539(43)# | 2# s [>300 ns] | β$^−$? | $^{227}$At | 5/2+# | |
| This table header & footer: view ||||||||||
* ↑ $^m$Po – Excited nuclear isomer.
* ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
* ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
* ↑ Bold italics symbol as daughter – Daughter product is nearly stable.
* ↑ Bold symbol as daughter – Daughter product is stable.
* ↑ ( ) spin value – Indicates spin with weak assignment arguments.
* 1 2 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
* ↑ Most common isotope
* 1 2 3 Intermediate decay product of $^{238}$U
* 1 2 Intermediate decay product of $^{235}$U
* 1 2 Intermediate decay product of $^{232}$Th
* 1 2 Intermediate decay product of $^{237}$Np
* ↑ Theoretically capable of β$^−$β$^−$ decay to $^{216}$Rn