Neptunium

Neptunium is a synthetic element in the periodic table that has the symbol Np and atomic number 93. A silvery radioactive metallic element, neptunium is the first transuranic element and belongs to the actinide series. Its most stable isotope, neptunium-237 is a by-product of nuclear reactors and plutonium production and it can be used as a component in neutron detection equipment. Neptunium is also found in trace amounts in uranium ores.

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Silvery in appearance, neptunium metal is fairly chemically reactive and is found in at least three structural modifications:

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• alpha-neptunium, orthorhombic, density 20,250 kg/m³,
• beta-neptunium (above 280^oC), tetragonal, density (313 ^oC) 19,360 kg/m³, and
• gamma-neptunium (above 577^oC), cubic, density (600^oC) 18,000 kg/m³.

This element has four ionic oxidation states while in solution:

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• Np⁺³ (pale purple), analogous to the rare earth ion Pm⁺³,
• Np⁺⁴ (yellow green);
• NpO²⁺ (green blue): and
• NpO²⁺⁺ (pale pink).

Neptunium forms tri- and tetrahalides such as NpF3, NpF4, NpCl4, NpBr3, NpI3, and oxides of the various compositions such as are found in the uranium-oxygen system, including Np3O8 and NpO2.

Neptunium: Notable characteristics ►



 

Synthetic element: The chemical elements labelled as "synthetic" are unstable, with a half-life so short (ranging from a fraction of millisecond to a few million years) relative to the age of the Earth that any atoms of that element that may have been present when the Earth formed have long since completely decayed aw...

Periodic table: The periodic table of the chemical elements, also called the Mendeleev periodic table, is a tabular display of the known chemical elements. First created by Dmitri Mendeleev, the elements are arranged by electron configuration so that many chemical properties follow a regular pattern across the tabl...

Atomic number: The atomic number (Z) is a term used in chemistry and physics to represent the number of protons found in the nucleus of an atom. In an atom of neutral charge, the number of electrons typically equals the atomic number....