n. [ after Pierre and Marie Curie. ] a radioactive transuranic element of atomic number 96, having an atomic weight of 247 for its most stable isotope (half-life 1.6 x 107 years). The chemical symbol is Cm. It was first prepared in 1944 by helium-ion bombardment of plutonium in a cyclotron by Glenn Seaborg and colleagues in California. It has never been detected in nature, though minute quantities may exist in uranium deposits as a consequence of the neutron flux there.
Syn. -- Cm, atomic number 96. [ WordNet 1.5 ]