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Neptunium

physical science Maturity 11-13 Next article →

Neptunium is a unique and heavy metal.

Np sphere
Np sphere

It is a radioactive actinide, which means it gives off radiation. This element is also poisonous and can build up in bones. Because of these traits, handling it is a very dangerous job.

Np(IV) in 8 M HCl.
Np(IV) in 8 M HCl.

It is the first transuranic element. This means it is the first element found after uranium on the periodic table. It is a hard and silvery metal. It can tarnish when it is left out in the air.

This metal works in a few different ways depending on its state. It has three different forms called allotropes. These forms change based on how hot the metal gets. For example, it changes at 280 degrees Celsius and again at 576 degrees Celsius.

Phase diagram of neptunium (1975)
Phase diagram of neptunium (1975)

Neptunium is also very dense. It is the densest of all the actinides. In fact, it is the fifth-densest element found in nature. It sits behind rhenium, platinum, iridium, and osmium in density.

Scientists first made neptunium in a laboratory. This happened in 1940 at the Berkeley Radiation Laboratory.

Berkeley 60-inch cyclotron
Berkeley 60-inch cyclotron

Two scientists named Edwin McMillan and Philip H. Abelson were the ones who first synthesized it. Before they succeeded, many people made false claims about finding it. Today, most neptunium is not found in the ground. Instead, it is made in nuclear reactors. It is often a by-product created when making power.

There are many different types of neptunium called isotopes. The most stable one is neptunium-237. It has a half-life of 2.144 million years.

Decay Chain(4n+1, Neptunium Series)
Decay Chain(4n+1, Neptunium Series)

Other isotopes like neptunium-239 have much shorter lives. Most other versions last for less than five days. Some neptunium is found in nature in tiny amounts. This happens in uranium ores through neutron capture reactions. These are tiny traces left behind by changes in the atoms.

Even though we do not use neptunium for many things yet, it is very helpful for space travel. It is used as a precursor to make plutonium-238. This material is used in radioisotope thermal generators. These tools provide electricity for spacecraft far away from Earth. Neptunium is also used in tools that detect high-energy neutrons. It helps us understand the tiny particles that move through space and machines.

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🖼️ Images & Media (9)
File:Phase diagram of neptunium (1975).png
Phase diagram of neptunium (1975).png
File:Decay Chain(4n+1, Neptunium Series).svg
Decay Chain(4n+1, Neptunium Series).svg
File:Np sphere.jpg
Np sphere.jpg
File:Mendelejevs periodiska system 1871.png
Mendelejevs periodiska system 1871.png
File:Berkeley 60-inch cyclotron.jpg
Berkeley 60-inch cyclotron.jpg
File:Neptunium Purex process.png
Neptunium Purex process.png
File:Np ox st.jpg
Np ox st.jpg
File:Np(IV) in 8 M HCl..jpg
Np(IV) in 8 M HCl..jpg
File:Neptunocene-from-xtal-3D-balls.png
Neptunocene-from-xtal-3D-balls.png
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