Element Curium, Cm

The member of actinide or actinoid group of chemical elements - Curium, an element of the actinide series, was first discovered (prepared) in 1944 by Glenn T. Seaborg with co-workers at the Metallurgical Laboratory of the University of Chicago by bombarding plutonium with helium ions. A pure compound, curium hydroxide was synthesized three years later. The element was named for Pierre and Marie (Maria) Curie, by analogy with gadolinium, a rare earth element with similar electron shell structure. The chemical symbol for curium is Cm, in which the first letter C is the initial of Curie and m is the initial of Marie.

Curium does not have stable isotopes. 15 isotopes with mass numbers from 237 to 251 are currently known. The most long-lived of them are ²⁴⁷Cm (T_1/2 1.58x10⁷ years) and ²⁴⁸Cm (T_1/2 3.4x10⁵ years), alpha-particle sources. The former has been found in the Earth's crust in some radioactive minerals, the parent of ²⁴³Pu ²³⁵U family.