Thallium-201 (Tl-201)

Identity

Protons

81

Neutrons

120

Mass number

201

Mass

201 ± 15 u

Mass excess

-27.181 MeV

Spin

1/2+*

Stability

Half-life: 3.04 days

Natural occurrence

Not found in nature

Decays to

• electron capture → Hg-201