neptunium-239 References neptunium-239 chemical isotope Ask Anything Homework Help Written by The Information Architects of Encyclopaedia Britannica The Information Architects maintain a master list of the topics included in the corpus of Encyclopædia Britannica, and create and manage the relationships between them. The Information Architects of Encyclopaedia Britannica Britannica AI Ask Anything Learn about this topic in these articles: uranium processing/ Conversion to plutoniumNeptunium-239 in turn undergoes beta decay, being transformed into plutonium-239 (atomic number 94). Read MoreNeptunium-239 in turn undergoes beta decay, being transformed into plutonium-239 (atomic number 94). Read More