meitnerium

Synthesized radioactive element of the transactinide series, atomic number 109, relative atomic mass 266. It was first produced in 1982 at the Laboratory for Heavy-Ion Research in Darmstadt, Germany, by fusing bismuth and iron nuclei; it took a week to obtain a single new, fused nucleus. It was known by the temporary name unnilennium until 1997 when it was named after the Austrian-born Swedish physicist Lise Meitner.