Ununpentium (IPA: /ˌjuːnʌnˈpɛntiəm/) is the temporary name of a synthetic superheavy element in the periodic table that has the temporary symbol Uup and has the atomic number 115. Multiple isotopes have been made by a fusion of calcium and americium (Uup-288 with the most neutrons). It can be referred to as eka-bismuth.
Element 115 also falls in the center of the theoretical island of stability. Although no stable isotopes have yet been found, conventional models predict that if stable isotopes of element 115 can be produced, they will most likely need the "magic number" of 184 neutrons, which would be Uup-299. The currently fabricated isotopes only had at most 173 neutrons (Uup-288).