It's Elemental - Isotopes of the Element Astatine

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Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information.

All Known Isotopes of the Element Astatine

Mass Number	Half-life	Decay Mode	Branching Percentage

193	40 milliseconds	Alpha Decay	No Data Available

193_m	≈ 40 milliseconds	Alpha Decay	No Data Available

194	≈ 40 milliseconds	Alpha Decay	No Data Available

194_m	≈ 250 milliseconds	Alpha Decay	No Data Available

195	146 milliseconds	Alpha Decay	100.00

195_m	0.39 seconds	Alpha Decay	No Data Available

		Electron Capture	No Data Available

196	0.253 seconds	Alpha Decay	> 0.00

197	0.37 seconds	Alpha Decay	96.00

		Electron Capture	4.00

197_m	3.7 seconds	Alpha Decay	<= 100.00

		Electron Capture	No Data Available

198	4.2 seconds	Alpha Decay	90.00

		Electron Capture	10.00

198_m	1.0 seconds	Alpha Decay	84.00

		Electron Capture	16.00

199	7.2 seconds	Alpha Decay	90.00

		Electron Capture	10.00

200	43 seconds	Alpha Decay	57.00

		Electron Capture	43.00

200_m	47 seconds	Electron Capture	<= 57.00

		Alpha Decay	43.00

200_m2	3.5 seconds	Isomeric Transition	~ 84.00

		Alpha Decay	~ 10.50

		Electron Capture	~ 4.50

201	89 seconds	Alpha Decay	71.00

		Electron Capture	29.00

202	184 seconds	Electron Capture	82.00

		Alpha Decay	18.00

202_m	182 seconds	Electron Capture	91.30

		Alpha Decay	8.70

202_m2	0.46 seconds	Isomeric Transition	99.70

		Electron Capture	0.25

		Alpha Decay	0.10

203	7.4 minutes	Electron Capture	69.00

		Alpha Decay	31.00

204	9.2 minutes	Electron Capture	96.20

		Alpha Decay	3.80

204_m	108 milliseconds	Isomeric Transition	100.00

205	26.2 minutes	Electron Capture	90.00

		Alpha Decay	10.00

206	30.6 minutes	Electron Capture	99.11

		Alpha Decay	0.89

207	1.80 hours	Electron Capture	91.40

		Alpha Decay	8.60

208	1.63 hours	Electron Capture	99.45

		Alpha Decay	0.55

209	5.41 hours	Electron Capture	95.90

		Alpha Decay	4.10

210	8.1 hours	Electron Capture	99.82

		Alpha Decay	0.18

211	7.214 hours	Electron Capture	58.20

		Alpha Decay	41.80

212	0.314 seconds	Alpha Decay	100.00

		Electron Capture	< 0.03

		Beta-minus Decay	< 2.0E-6

212_m	0.119 seconds	Alpha Decay	> 99.00

		Isomeric Transition	< 1.00

213	125 nanoseconds	Alpha Decay	100.00

214	558 nanoseconds	Alpha Decay	100.00

215	0.10 milliseconds	Alpha Decay	100.00

216	0.30 milliseconds	Alpha Decay	100.00

		Beta-minus Decay	< 6.0E-3

		Electron Capture	< 3.0E-7

217	32.3 milliseconds	Alpha Decay	99.99

		Beta-minus Decay	0.01

218	1.5 seconds	Alpha Decay	99.90

		Beta-minus Decay	0.10

219	56 seconds	Alpha Decay	~ 97.00

		Beta-minus Decay	~ 3.00

220	3.71 minutes	Beta-minus Decay	92.00

		Alpha Decay	8.00

221	2.3 minutes	Beta-minus Decay	100.00

222	54 seconds	Beta-minus Decay	100.00

223	50 seconds	Beta-minus Decay	100.00