Atomic number: 93
Density at 25°C: solid: density: 20.45 g·cm−3
Named after the god of the ocean, neptunium tends to be quite a rare element only occurring in trace amounts in uranium ores. It mainly comes from nuclear reactors.
Use, natural applications or common combinations:
- nuclear reactor radioactive waste
- military uses
- Standard atomic weight: 237.048
- Melting point: (637) 644 °C
- Boiling point: 3902 °C
- Radioactivity: all radioactive
- 238Np with a half-life of 4.47 billion years emitting alpha particles
- 235Np with a half-life of 704 million years, spontaneous fission decay process.