A radioactive element; atomic no. 93; first element of the transuranian series (not found in nature); 237Np has a half-life of 2.14 × 106 years. [planet, Neptune]

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nep·tu·ni·um nep-'t(y)ü-nē-əm n a radioactive metallic element that is chemically similar to uranium and is obtained in nuclear reactors as a by-product in the production of plutonium symbol Np see ELEMENT (table) Nep·tune 'nep-.t(y)ün Roman mythological character. Neptune was originally the god of fresh water. Later he became identified with the Greek god Poseidon, a deity of the sea. In art Neptune is usually represented as a bearded man holding a trident and sometimes a fish. The planet Neptune was named after him and the element neptunium was named after the planet.

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nep·tu·ni·um (Np) (nep-tooґne-əm) [from planet Neptune] a radioactive element of atomic number 93 and atomic weight 237, occurring in certain earths and obtained by splitting the uranium atom with neutrons. It is unstable and changes into plutonium.

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  • Neptunium — Uranium ← Neptunium → Plutonium Pm …   Wikipédia en Français

  • NEPTUNIUM — Élément chimique de numéro atomique 93, le neptunium (symbole Np) est le premier membre de la série d’éléments lourds artificiels: les transuraniens. Comme tous ces éléments, il a de nombreux isotopes qui sont tous radio actifs et produits… …   Encyclopédie Universelle

  • Neptunium — Nep*tu ni*um, n. [NL.] A radioactive metallic element of atomic number 93, produced in nuclear reactors from Plutonium or Uranium. Symbol Np; The atomic weight of the most stable isotope is 237.0482. [PJC] …   The Collaborative International Dictionary of English

  • NEPTUNIUM — alias Navale Antiatum, oppid. ditionis Pontificiae cum portu tantisper capaci, in Latio, in ora maris Tyrrheni alias sub dominio utili Columnarum, medium inter Terracinam ad Ortum et ostia Tiberina ad Occasum, 25. milliar. utrinque, versus… …   Hofmann J. Lexicon universale

  • neptunium — Symbol: Np Atomic number: 93 Atomic weight: (237) Radioactive metallic transuranic element, belongs to the actinoids. Np 237, the most stable isotope, has a half life of 2.2*10^6 years and is a by product of nuclear reactors. The other known… …   Elements of periodic system

  • neptunium — (n.) 1941, from NEPTUNE (Cf. Neptune) + element ending ium. Named for its relative position in the periodic table, next after URANIUM (Cf. Uranium), as the planet Neptune is one beyond Uranus. Cf. also PLUTONIUM (Cf. plutonium) …   Etymology dictionary

  • neptunium — ☆ neptunium [nep to͞o′nē əm, neptyo͞o′nē əm ] n. [ModL < Neptunus, NEPTUNE + IUM: so named by MCMILLAN Edwin MattisonEdwin MattisonEdwin MattisonEdwin MattisonEdwin MattisonEdwin Mattison & P. Abelson (1913 2004), U.S. phys i cists, because… …   English World dictionary

  • Neptunium — uranium ← neptunium → plutonium Pm ↑ Np ↓ (Uqt) …   Wikipedia

  • Neptunium — Eigenschaften …   Deutsch Wikipedia

  • neptunium — /nep tooh nee euhm, tyooh /, n. Chem., Physics. a transuranic element produced in nuclear reactors by the neutron bombardment of U 238: decays rapidly to plutonium and then to U 235. Symbol: Np; at. no.: 93. [1940 45; NEPTUNE + IUM] * * * ▪… …   Universalium

  • Neptunium — Nep|tu|ni|um 〈n.; s; unz.; chem. 〉 künstliches radioaktives Element, Ordnungszahl 93 [neulat., nach dem Planeten Neptun] * * * Nep|tu|ni|um [nach dem Planeten Neptun, der nach dem Uranus (↑ Uran) entdeckt wurde; ↑ ium (1)], das; s; Symbol: Np: in …   Universal-Lexikon

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