Heavy Elements

The periodic table officially has a new entry. The International Union of Pure & Applied Chemistry announced its approval last week of the name copernicium and symbol Cn for element 112 (Pure Appl. Chem., DOI: 10.1351/PAC-REC-09-08-20).

The approval follows IUPAC’s extensive review of claims made by the GSI Helmholtz Center for Heavy Ion Research, in Darmstadt, Germany, of being the first team to synthesize element 112. GSI’s claims date back to 1996. IUPAC’s announcement raises to six the total number of elements officially discovered and named by GSI.

GSI team leader Sigurd Hofmann explains that his team’s intention in selecting the name for element 112 is “to salute Nicolaus Copernicus, an influential scientist who didn’t receive any accolades in his own lifetime, and to highlight the link between astronomy and the field of nuclear chemistry.” Copernicus was the 16th-century Polish astronomer who developed the sun-centered model of the solar system—a radical departure from the thinking that prevailed in Copernicus’ day.

The Darmstadt researchers have previously been recognized for the discovery of five other elements, which they named bohrium (107), hassium (108), meitnerium (109), darmstadtium (110), and roentgenium (111).

Initially the team proposed Cp as the symbol for copernicium. But IUPAC did not approve that symbol principally because it had been used previously for element 71, lutetium, which, prior to 1949, was also known as cassiopeium.