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Actinium

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Protactinium

Isotopes of the Element Thorium

[Click for Main Data]

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

Naturally Occurring Isotopes

Mass NumberNatural AbundanceHalf-life
232100%1.40×1010 years

Known Isotopes

Mass NumberHalf-lifeDecay ModeBranching Percentage
2081.7 millisecondsAlpha Decay100.00%
2092.5 millisecondsAlpha DecayNo Data Available
21016 millisecondsElectron Capture~ 1.00%
Alpha Decay99.00%
2110.04 secondsAlpha DecayNo Data Available
21231.7 millisecondsAlpha Decay100.00%
Electron Capture~ 0.30%
213144 millisecondsAlpha Decay<= 100.00%
21487 millisecondsAlpha Decay100.00%
2151.2 secondsAlpha Decay100.00%
21626.0 millisecondsAlpha Decay100.00%
Electron Capture~ 0.01%
216m134 microsecondsAlpha Decay2.80%
Isomeric TransitionNo Data Available
2170.241 millisecondsAlpha Decay100.00%
218117 nanosecondsAlpha Decay100.00%
2191.05 microsecondsAlpha Decay100.00%
2209.7 microsecondsAlpha Decay100.00%
Electron Capture2.0×10-7 %
2211.68 millisecondsAlpha Decay100.00%
2222.8 millisecondsAlpha Decay100.00%
2230.60 secondsAlpha Decay100.00%
2240.81 secondsAlpha Decay100.00%
2258.75 minutesElectron Capture~ 10.00%
Alpha Decay~ 90.00%
22630.57 minutesAlpha Decay100.00%
22718.68 daysAlpha Decay100.00%
2281.9116 yearsAlpha Decay100.00%
Emission of an oxygen-20 nucleus1×10-11 %
2297932 yearsAlpha Decay100.00%
229m2 minutesIsomeric Transition (suspected)No Data Available
2307.54×10+4 yearsAlpha Decay100.00%
Emission of a neon-24 nucleus6×10-11 %
Spontaneous Fission<= 4×10-12 %
23125.52 hoursAlpha Decay~ 4×10-11 %
Beta-minus Decay100.00%
2321.40×1010 yearsAlpha Decay100.00%
Spontaneous Fission1.1×10-9 %
23321.83 minutesBeta-minus Decay100.00%
23424.10 daysBeta-minus Decay100.00%
2357.2 minutesBeta-minus Decay100.00%
23637.3 minutesBeta-minus Decay100.00%
2374.7 minutesBeta-minus Decay100.00%
2389.4 minutesBeta-minus Decay100.00%
239No Data AvailableNo Data AvailableNo Data Available