Atomic number 93 occurs as synthetic element in the periodic table that has the symbol Np & atomic number 93. The silvery radioactive metallic element, neptunium is the 1st transuranic element and belongs to the actinide series. Its virtually all stable isotope, neptunium-237 is a by-product of nuclear reactors and plutonium production and it may be utilized as a component within neutron detection equipment. Atomic number 93 is besides obtained inside trace numbers inside uranium ores.

Notable characteristics
Silvery inside appearance, np metal is fairly chemically reactive and is found inside at least trinity structural modifications: alpha-neptunium, orthorhombic, density 20,250 kg/m^Trey, beta-neptunium (above 280^oC), tetragonal, density (313 ^oC) 19,360 kg/m³, and gamma-neptunium (above 577^oC), three-dimensional, density (600^oC) 18,000 kg/m^Triad.

This element has iv ionic oxidation states while in guide: Np⁺³ (blanch purple), correspondent to the uncommon globe ion P.m.⁺³, Np⁺⁴ (yellow green); NpO²⁺ (green blue): and NpO²⁺⁺ (blanch pink).

Np forms tri- & tetrahalides such as NpF₃, NpF₄, NpC_l4, NpBr₃, NpI₃, and oxides of the various compositions such as come detected in the uranium-oxygen system, including Np₃O_{Eighter from decatur} & NpO_Two.

History
Np (known as for the planet Neptune) was first discovered by Edwin McMillan and Philip Abelson in 1940. A discovery was manufactured at a Berkeley Radiation Laboratory of the University of California, Berkeley where a team produced the np isotope Np-239 (2.Quadruplet day half-life) by bombarding uranium with slow moving neutrons. It was a number 1 transuranium element produced synthetically and a foremost actinide series transuranium element discovered.

Occurrence
Trace numbers of atomic number 93 come noticed naturally when decay products from transmutation reactions in uranium ores. Np-237 is produced through the reduction of NpF₃ by owning barium or lithium vapor at around 1200 ° C and is most typically extracted from either spent nuclear fuel rods as a by-product in plutonium production.

Isotopes
Nineteen atomic number 93 radioisotopes have been characterized, sustaining the virtually all stalls existence Np-237 with a half-life of 2.14 million years, Np-236 sustaining the half-life of 154,000 years, & Np-235 using the half-life of 396.Single years. Tons of the left radioactive isotopes have half-lifes that come less than Quadruplet.Cinque years, & a majority one use at times half lifes that come less than Fifty transactions. This element besides has Little joe meta states, with a virtually all stalls existence Np-236m (t_½ Xxii.Cinque hours).

A isotopes of np home in atomic weight from 225.0339 u (Np-225) to 244.068 u (Np-244). A primary decay mode before the virtually all stable isotope, Np-237, is electron capture (with a lot of alpha emission), and a primary mode when is beta emission. A primary decay products before Np-237 come element 92 (uranium) isotopes (alpha emission produces element 91, protactinium, however) & a primary products when come element 93 (plutonium) isotopes.

Weapons applications

Within September, 2002, investigator for the University of California conducting research for the United States of America nuclear weapons development program created the first nuclear critical mass applying atomic number 93 like than atomic number 94 or even u. United states officials inside March, 2004, planned to move a united states's supply of enriched np to the places within Nevada.