Neptunium () iku unsur kimia kanthi simbul Np lan nomer atom 93.

Rujukan 

 Los Alamos National Laboratory's Chemistry Division: Periodic Table - Neptunium 
 Guide to the Elements - Revised Edition, Albert Stwertka, (Oxford University Press; 1998) ISBN 0-19-508083-1

Pranala njaba 

 WebElements.com - Neptunium (also used as a reference)
 Lab builds world's first neptunium sphere , U.S. Department of Energy Research News
 NLM Hazardous Substances Databank – Neptunium, Radioactive

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