Neptunium - Np
Neptunium (Np)
Neptunium is a radioactive actinide produced mainly in nuclear reactors. Trace quantities occur naturally in uranium ores, but most neptunium is associated with nuclear fuel-cycle materials.
| Atomic number | 93 |
|---|---|
| Representative isotope mass number | [237] (representative isotope mass number) |
| Electron configuration | [Rn] 5f4 6d1 7s2 |
| Density | 20.2 (reported) g/cm3 |
| Melting point | 644 °C |
| Boiling point | 3902 °C |
Uses and applications
Neptunium has few applications outside research. Neptunium-237 has been used in specialised neutron-detection applications.
Neptunium and water management
Neptunium is not used in conventional water treatment. If present in water from nuclear facilities or related operations, it requires isotope-specific radiological monitoring and waste management under applicable controls.
Occurrence and environmental context
Neptunium is an actinide, and its occurrence and environmental behaviour depend on isotope, chemical form, and source. Natural geology, mineral processing, and nuclear-related activities can each affect whether an actinide is present in a water or waste stream. Monitoring should distinguish chemical concentration from radioactive activity where relevant.
Health and safety
Neptunium requires careful handling because of its radioactive properties; for some elements, chemical toxicity is also relevant. Exposure depends on isotope, activity, chemical form, and route. Follow applicable radiation-protection procedures and substance-specific safety information.
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Sources and further reading
Element page last reviewed: 24 October 2026 by Lenntech.