Initial radionuclides existing since the earth was formed and which have not completely decayed due to their long half-life in addition to the radionuclides generated from the primordial radionuclides U 238, U 235 and Th 232 of the associated decay chain.

Nuclide half-life
Nuclide

half-life

K-40

1.3*109

La-138

1.1*1011

V-50

1.4*1017

Nd-144

2.3*1015

Ge-76

1.5*1021

Nd-150

1.7*1019

Se-82

1.0*1020

Sm-147

1.1*1011

Rb-87

4.8*1010

Sm-148

7.0*1015

Zr-96

3.9*1019

Gd-152

1.1*1014

Mo-100

1.2*1019

Lu-176

2.6*1010

Cd-113

9.0*1015

Hf-174

2.0*1015

Cd-119

2.6*1019

Ta-180

1.2*1015

In-115

4.4*1014

Re-187

5.0*1010

Te-123

1.2*1013

Os-186

2.0*1015

Te-128

7.2*1024

Pt-190

6.5*1011

Te-130

2.7*1021

Bi-209

1.9*1019

Primordial radionuclides outside of decay chains