Topic summary
Neptunium-237
Extracted from the Wikipedia article Isotopes of neptunium.
Neptunium-237
Np decays via the neptunium series, which terminates with thallium-205, which is stable, unlike most other actinides, which decay to stable isotopes of lead. Until the discovery of its alpha decay (with an extremely long half-life), the series was thought to end with bismuth-209.