Group 12 element precludes there being much common chemistry between mercury and gold, though there are similarities between mercury(I) and gold(I) such as the formation of linear dicyano complexes, [M(CN)]. According to IUPAC's definition of transition metal as "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell", zinc and cadmium are not transition metals, while mercury is. This is because only mercury is known to have a compound where its oxidation state is higher than +2, in mercury(IV) fluoride (though its existence is disputed, as later experiments trying to confirm its
Group 8 element Group 8 element Group 8 is a group of chemical element in the periodic table. It consists of iron (Fe), ruthenium (Ru), osmium (Os) and hassium (Hs). They are all transition metals. Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior. "Group 8" is the modern IUPAC name for this group; the old style name was "group VIIIB" in the CAS, US system or "group VIIIA" in the old IUPAC, European system. Group 8 should not be confused with the old-style group name of "VIIIA"