neptunium

Traductions

• anglais

  Date : 1983

  Définition

  An element. State: Solid; Group: IIIB (Actinide Series); Atomic No: 93; Atomic Wt: 237.0482; Valence 3,4,5,6. An artificial radioactive metal, m.p. 640 °C (1184 °F), made from uranium by neutron bombardment; it was discovered during experiments with the cyclotron in 1940. The 239 isotope decays quickly to plutonium, but the 237 isotope is comparatively stable.

  Note :

  It is produced during the reactor synthesis of plutonium, existing as a reactive metal which behaves as a strong reducing agent. It is now made in small quantities (less than one pound). It forms a large number of compounds.

  Termes :

  1. neptunium
  2. Np

  [Np] Symbol for the element neptunium, named for the planet Neptune, which is next beyond Uranus in the solar systen, as neptunium is the next element beyond uranium in the Periodic System.