curium

noun

Etymology: From Curie + -ium (suffix forming names of metallic elements), coined by the American scientists Glenn T. Seaborg (1912–1999), Ralph A. James (1920–1973), and Albert Ghiorso (1915–2010), who synthesized the element in 1944 and named it in honour of Pierre Curie (1859–1906) and Marie Skłodowska Curie (1867–1934) who, with Henri Becquerel, were awarded the 1903 Nobel Prize in Physics for discoveries in radioactivity.

1. A radioactive and highly fissile, silver-grey, metallic, transuranic chemical element (symbol Cm) with an atomic number of 96, which is artificially produced in a particle accelerator.

   “Curium was the third transuranium element to be discovered. The first isotope of this element was the isotope, Cm²⁴², which was identified by G. T. Seaborg, R. A. James and A. Ghiorso at the Metallurgical Laboratory as the result of its production in the Berkeley cyclotron […] The availability of this isotope of curium made it possible to study the chemical properties of this element by the use of the tracer technique. Extensive investigations have led to the conclusion that curium probably exists exclusively in the III oxidation state in aqueous solution.”

   “The chemical properties of americium and curium may be summarized in the statement that they bear a striking resemblance to the rare earth elements, particularly those of atomic numbers 60 to 64. […] Thus the chemical properties of americium and curium support the view that these elements are members of an actinide series in which the 5f electron shell is being filled just as the 4f shell is being filled in the rare earth series. Curium is believed to possess seven 5f electrons just as gadolinium possesses seven 4f electrons.”