Meaning of neptunium

nep•tu•ni•um

Pronunciation: (nep-t'nē-um, -ty'-), [key]
— n. Chem., Physics.
  1. 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.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
See also: