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Periodic Table of Elements

Np - Neptunium

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Nuclides / Isotopes

Nuc-
lide
Atomic
Mass
NNAbun
%
SpinHalf LifeDMDTBR
%
Decay
Energy
(MeV)
Np225225.0339132Syn 6ms    
Np226226.0351133Syn 35msαPa222 8.200
Np227227.035134Syn 0.51sαPa223 7.816
Np228228.036135Syn 61.4s εU228604.480
 61.4sαPa224407.420
Np229229.0362136Syn 4mαPa225>507.010
 4m εU229<502.560
Np230230.0378137Syn 4.6m εU230<=973.610
 4.6mαPa226>=36.780
Np231231.0382138Syn5/248.8m εU231981.840
 48.8mαPa22726.370
Np232232.04139Syn4+14.7m εU232 2.700
Np233233.0407140Syn5/2+36.2mαPa229 5.830
 36.2m εU233 1.230
Np234234.0429141Syn0+4.4d εU234 1.810
Np235235.0441142Syn5/2+396.1dαPa2310.00265.192
 396.1d εU235 0.124
Np236236.0466143Syn6-154000y εU23687.300.940
 154000y β-Pu23612.500.940
 154000yαPa2320.165.020
meta state 0.060MeVSyn122.5h εU236521.000
 22.5h β-Pu236480.550
Np237237.0482144Syn5/2+2144000ySF <=2E -10 
 2144000yαPa233 4.959
meta state 2.800MeVSyn 45nsSF <=100 
Np238238.0509145Syn2+2.117d β-Pu238 1.292
Np239239.0529146Syn5/2+2.3565d β-Pu239 0.722
Np240240.0562147Syn5+61.9m β-Pu240 2.200
meta state 0.000MeVSyn1+7.22m β-Pu24099.892.200
 7.22mIT   
Np241241.0582148Syn5/2+13.9m β-Pu241 1.310
Np242242.062149Syn65.5m β-Pu242 2.700
meta state 0.000MeVSyn1+2.2m β-Pu242 2.700
Np243243.0643150Syn5/2-1.8m β-Pu243 2.170
Np244244.068151Syn7-2.29m    
NuclidePotential Parent Nuclides
Np225None known
Np226None known
Np227None known
Np228Am232 (Syn)
Np229None known
Np230Am233 (Syn)
Np231None known
Np232Am236 (Syn) Pu232 (Syn)
Np233Am237 (Syn) Pu233 (Syn)
Np234Am238 (Syn) Pu234 (Syn)
Np235Am239 (Syn) Pu235 (Syn)
Np236Am240 (Syn)
meta state 0.060MeVNone known
Np237Am241 (Syn) Pu237 (Syn) U237 (Syn)
meta state 2.800MeVNone known
Np238Am242m (Syn) Am242m1 (Syn)
Np239Am243 (Syn) U239 (Syn)
Np240U240 (Syn)
meta state 0.000MeVNone known
Np241None known
Np242U242 (Syn)
meta state 0.000MeVNone known
Np243None known
Np244None known

Key:

  • NN = Number of Neutrons
  • Abun % = Natural Abundance (as a percentage)
  • Syn = Synthetic Nuclide (does not occur in nature)
  • DM = Decay Mode
    α = Alpha emission
    β- = Beta emission
    β- β- = Double beta decay
    β+ = Positron emission
    ε = Electron Capture
    IT = Isomeric Transition
    N = Neutron emission
    P = Proton emission
    SF = Spontaneous Fission
  • DT = Decays To
  • BR % = Branch Ratio (as a percentage)

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