Hahnium (Ha) is a synthetic, radioactive, transactinide element. It has atomic number 105; six isotopes have been synthesized. It was first reported by a Soviet team at the Joint Institute for Nuclear Research at Dubna. They claimed the isotopes of mass numbers 260 and 261, as a result of bombarding americium with neon ions. In 1970 a team at the University of California claimed the isotope 260 (half-life 1.6 seconds) obtained by bombarding californium with nitrogen nuclei. The element is named after Otto Hahn.