copper group element atom roentgenium atom 0 0.000 0.00000 111Rg A copper group element atom with atomic number 111. The the ninth member of the 6d series of transition metals, it is an extremely radioactive, synthetic element. Average mass is around 281. CHEBI:33368 InChI=1S/Rg LJROPTGWFUZRDB-UHFFFAOYSA-N Rg Rg Roentgenium Uuu WebElements:Rg Wikipedia:Roentgenium [Rg] chebi_ontology roentgenio roentgenium roentgenium unununium roentgentio roentgentium Roentgentium roentgentio 錀