uranium ⟵ {\displaystyle \longleftarrow } 93 ⟶ {\displaystyle \longrightarrow } plutonium The Simple English Wikipedia has an article on: Neptunium Pronunciation enPR: nĕptū'nēəm, IPA (key): /nɛpˈtjuːniəm/ enPR: nĕpto͞o'nēəm, IPA (key): /nɛpˈtuːniəm/ Audio (UK)(file) Audio (US)(file) Noun Singular neptunium Plural none Neptunium is a chemical element with atomic number 93 and symbol Np. This short entry needs someone to make it better. You can help Wiktionary by adding to it.Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads