Neptunium Facts

American physicist and Nobel laureate Edwin McMillanm, and Philip H. Abelson, a physicist and a scientific editor, are known to be the people who were responsible for adding one more element to the Mendeleev's Periodic table - neptunium. As mentioned, this element has been named after the planet Neptune. It was in 1940, at Berkeley Radiation Laboratory of the University of California, Berkeley, when neptunium was discovered. The chemical elements which possess an atomic number that is greater than 92 are known by the name 'transuranic elements'. And neptunium, a radioactive metallic element, is known to be the first of such elements.

Neptunium Element Facts

Neptunium Properties
Symbol	Np
Atomic Number (No. of protons or electrons)	93
Atomic Mass	237.0482 amu (atomic mass unit)
Electronic Configuration	5f4 6d1 7s2
Number of Neutrons	144
Melting Point	913 K (Kelvin)
Boiling Point	4175 K
Crystal Structure (Lattice Structure)	Orthorhombic
Density	20.25 g/cc
Atomic Radius	130 pm
Oxidation States	6, 5, 4, 3
Evaporation Heat	336 kJ/mol
Atomic Volume	21.1 cc/mol

Isotopes of Neptunium

Isotopes are known to be among the most important parts of an element. They are simply defined as one of two or more atoms, which although have the same atomic number, have different number of neutrons. For this element, there are 20 isotopes known till date. The element neptunium is not stable and it decays radioactively into other elements. That is why it has an extremely short half life thus, making it rare and even non-existent in some parts of the Earth. One isotope of this element which is known to be the most stable is neptunium-237. It has a half-life of 2.14 million years.

Neptunium Uses

As mentioned neptunium-237 is the most stable isotope of this element, and it is this that is employed in various processes. It is used in neutron-detection equipment. It is bombarded with neutrons for the production of plutonium-238 (radioactive isotope of plutonium; half-life of 87.7 years).

Neptunium may also finds applications in weaponry, but theoretically. It has the property to sustain a chain reaction of nuclear fission. Although there has been no procedure which used this element for the manufacture of weapon, according to the U.S. Department of Energy, it can be used for such purposes. And because of this, in some regions in the world, its access is restricted.

Apart from this, the radioactive element is also employed for high-energy (MeV) neutrons.

Some More Facts About Neptunium

• Usually, reaction between two metals is rare. However, given to the reactive nature of this element, it form compounds like neptunium dialuminide (NpAL 2 ) and neptunium beryllide (NpBe 3 ).
• Earlier, this element was assumed to be man-made, in other words, artificial. However, it was later discovered that trace amounts of the element are present in the Earth's crust. Also, although rare, it is also found in uranium ores and in that of other radioactive elements.

Neptunium is one of those elements which are considered harmful to living beings. Due to obvious reasons, the radiation emitted by the substance results into severe health conditions, both in humans and animals. This type of radiation does not kill but damage the body cells, which in turn may lead to abnormal cell reproduction.