noun
- a radioactive metallic chemical element with the symbol Np and atomic number 93
Usage: chemistry
Examples
- Neptunium was the first transuranium element to be artificially produced.
- Scientists created neptunium by bombarding uranium with neutrons.
- Neptunium-237 has a half-life of over two million years.
- The element neptunium was named after the planet Neptune.
- Neptunium is used in neutron detection equipment.
- Small amounts of neptunium occur naturally in uranium ores.