Thorium-227 (Th-227)

Identity

Protons

90

Neutrons

137

Mass number

227

Mass

227.0 ± 2.2 u

Mass excess

25.805 MeV

Spin

(1/2+)

Stability

Half-life: 18.7 days

Natural occurrence

Not found in nature

Decays to

• alpha → Ra-223

Produced by

• Ac-227
• U-231