Thorium-229 (Th-229)

Identity

Protons

90

Neutrons

139

Mass number

229

Mass

229.0 ± 2.6 u

Mass excess

29.586 MeV

Spin

5/2+*

Stability

Half-life: 7916 years

Natural occurrence

Not found in nature

Decays to

• alpha → Ra-225

Produced by

• Pa-229
• U-233