Periodic Table/Thorium/²²¹Th

← 220Th222Th →

²²¹Th

Thorium-221

Radioactive· Half-life: 1.75 ms

Nuclear Propertiesbinding energy · spin-parity · abundance

Protons (Z)

90

Neutrons (N)

131

Mass Number (A)

221

Atomic Mass

221.018186AMU

Spin / Parity

7/2+

Binding E/A

7.468keV

Natural Abundance

Trace / None

Half-life

1.75 ms

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

α

100.0%

Decay Chain

²²¹ThThorium1.75 ms

α100.0%

²¹⁷RaRadium1.95 μs

α100.0%

²¹³RnRadon19.5 ms

α100.0%

²⁰⁹PoPolonium124 y

α99.5%

β⁺²⁰⁹Bi0.45%

²⁰⁵PbLead17.0 My

EC100.0%

²⁰⁵TlThalliumSTABLE

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

Other Isotopes of Thorium

208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239

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