On February 2, 2004, scientists working at the Joint Institute for Nuclear Research in Dubna, Russia, along with scientists from the U.S. Department of Energy's Lawrence Livermore National Laboratory, announced the creation of ununpentium. In experiments performed between July 14, 2003 and August 10, 2003, atoms of americium-243 were bombarded with ions of calcium-48 using a device called a cyclotron. This produced one atom of ununpentium-287 and three atoms of ununpentium-288. All four atoms quickly decayed into other elements.

Ununpentium's most stable isotope, ununpentium-288, has a half-life of about 87 milliseconds. It decays into ununtrium-284 through alpha decay.

Since only a few atoms of ununpentium have ever been produced, it currently has no uses outside of basic scientific research.