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Isotopes of the Element Neptunium

[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

Neptunium has no naturally occurring isotopes.

Known Isotopes

Mass NumberHalf-lifeDecay ModeBranching Percentage
225No Data AvailableAlpha Decay100.00%
22635 millisecondsAlpha Decay100.00%
2270.51 secondsAlpha Decay100.00%
22861.4 secondsElectron Capture60.00%
Alpha Decay40.00%
2294.0 minutesAlpha Decay68.00%
Electron Capture32.00%
2304.6 minutesElectron Capture<= 97.00%
Alpha Decay>= 3.00%
23148.8 minutesElectron Capture98.00%
Alpha Decay2.00%
23214.7 minutesElectron Capture100.00%
Alpha Decay2.0×10-4 %
23336.2 minutesElectron Capture100.00%
Alpha Decay<= 1.0×10-3 %
2344.4 daysElectron Capture100.00%
235396.1 daysElectron Capture100.00%
Alpha Decay2.6×10-3 %
236153×10+3 yearsElectron Capture86.30%
Beta-minus Decay13.50%
Alpha Decay0.16%
236m22.5 hoursBeta-minus Decay50.00%
Electron Capture50.00%
2372.144×10+6 yearsAlpha Decay100.00%
Spontaneous Fission<= 2×10-10 %
2382.117 daysBeta-minus Decay100.00%
2392.356 daysBeta-minus Decay100.00%
24061.9 minutesBeta-minus Decay100.00%
240m7.22 minutesBeta-minus Decay99.88%
Isomeric Transition0.12%
24113.9 minutesBeta-minus Decay100.00%
2422.2 minutesBeta-minus Decay100.00%
242m5.5 minutesBeta-minus Decay100.00%
2431.85 minutesBeta-minus Decay100.00%
2442.29 minutesBeta-minus Decay100.00%
245No Data AvailableNo Data AvailableNo Data Available