Periodic Table/Astatine/²⁰⁹At

← 208At210At →

²⁰⁹At

Astatine-209

Radioactive· Half-life: 5.42 h

Nuclear Propertiesbinding energy · spin-parity · abundance

Protons (Z)

85

Neutrons (N)

124

Mass Number (A)

209

Atomic Mass

208.986169AMU

Spin / Parity

9/2-

Binding E/A

7.607keV

Natural Abundance

Trace / None

Half-life

5.42 h

Decay Modesoverview · half-life · α · β⁻ · β⁺

β⁺

96.1%

α

3.9%

Decay Chain

²⁰⁹AtAstatine5.42 h

β⁺96.1%

α²⁰⁵Bi3.90%

²⁰⁹PoPolonium124 y

α99.5%

β⁺²⁰⁹Bi0.45%

²⁰⁵PbLead17.0 My

EC100.0%

²⁰⁵TlThalliumSTABLE

4-step decay chain → stable · Primary path shown · branching ratios indicated

Other Isotopes of Astatine

191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229

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