Isotopes of polonium

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.

List of isotopes

Nuclide	Historic name	Z	N	Isotopic mass (Da)	Discovery year	Half-life	Decay mode	Daughter isotope	Spin and parity	Isotopic abundance
Excitation energy
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		4(27) keV	(2006)	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	Radium F	84	126	209.9828737(12)		138.376(2) d	α	206Pb	0+	Trace
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
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
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
214Po	Radium C'	84	130	213.9952013(16)		163.47(3) μs	α	210Pb	0+	Trace
215Po	Actinium A	84	131	214.9994184(23)		1.781(5) ms	α	211Pb	9/2+	Trace
β− (2.3×10−4%)	215At
216Po	Thorium A	84	132	216.0019134(19)		143.7(5) ms	α	212Pb	0+	Trace
217Po		84	133	217.006316(7)		1.53(5) s	α (97.5%)	213Pb	(9/2+)	Trace
β− (2.5%)	217At
218Po	Radium A	84	134	218.0089712(21)		3.097(12) min	α (99.98%)	214Pb	0+	Trace
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+#
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Daughter products other than polonium