Thorium series

The thorium series is the natural decay series of the thorium isotope ²³² Th. Its end nuclide is the lead isotope ²⁰⁸ Pb. Because the starting nuclide of the series is the plutonium isotope ²⁴⁴ Pu, which occurs in very small quantities in nature , the series begins there. However, it is named after the most common nuclide ²³² Th.

Natural radioactive decay series: Thorium series (blue)

4 n row

Decay series of ²⁴⁴ Pu ; Z shows the atomic number (number of protons), N the number of neutrons of the isotopes

nuclide	Decay	Half-life	E / MeV	Decay product
244 Pu	α 99.879% SF 0.121%	80 · 10 6 a	4.666  ?	240 U  ?
240 U	β -	14.1 h	0.4	240 Np
240 Np	β -	65 min	0.9	240 pu
240 pu	α	6564 a	5.256	236 U
236 U	α	2.3 · 10 7 a	4.494	232 Th
232 Th	α, γ	1.405 x 10 10 a	4.083	228 ra
228 ra	β -	5.75 a	0.046	228 Ac
228 Ac	β -	6.15 h	2.127	228 Th
228 Th	α	1.9131 a	5.520	224 ra
224 ra	α	3.66 d	5.789	220 para
220 para	α	55.6 s	6.405	216 Po
216 Po	α	0.145 s	6,906	212 Pb
212 Pb	β -	10.64 h	0.574	212 bi
212 bi	β - 64.06% α 35.94%	60.55 min	2.254 6.207	212 Po 208 Tl
212 Po	α	2.99 · 10 −7 s	8,954	208 Pb
208 Tl	β -	3.083 min	5.001	208 Pb
208 Pb	.	Stable	.	.