Table 2

Selected isotope mass existing at specified time

IsotopeInitial mass, gMass at 1.5 × 109 years, gMass at 3.0 × 109 years, gMass at 4.5 × 109 years, g
230Th0.01.896  × 10141.160  × 10146.157  × 1013
232Th0.02.392  × 10173.664  × 10173.896  × 1017
231Pa0.04.048  × 10132.100  × 10131.277  × 1013
233Pa0.04.696  × 1061.039  × 1071.581  × 107
232U0.04.339  × 1063.966  × 1063.641  × 106
233U0.01.011  × 10132.237  × 10133.403  × 1013
234U0.06.209  × 10143.798  × 10142.015  × 1014
235U4.867 × 10188.844  × 10174.585  × 10172.782  × 1017
236U0.05.940  × 10155.312  × 10154.941  × 1015
237U0.03.339  × 1053.533  × 1053.283  × 105
238U1.606  × 10191.148  × 10197.024  × 10183.726  × 1018
237Np0.03.855  × 10134.032  × 10133.911  × 1013
238Pu0.02.338  × 1064.303  × 1066.296  × 106
239Pu0.03.969  × 10134.288  × 10133.498  × 1013
240Pu0.04.937  × 1079.399  × 1071.154  × 108
241Pu0.01.792  × 10−15.986  × 10−11.111  × 100
241Am0.05.402  × 1001.805  × 1013.348  × 101