Group-09-Cobalt
#chemic/Group
Group 9, by modern IUPAC numbering, is a group (column) of chemical elements in the periodic table. Members of Group 9 include cobalt (Co), rhodium (Rh), iridium (Ir) and meitnerium (Mt). These are all transition metals in the d-block, considered to be some of the most rare of which.Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior; however, rhodium deviates from the pattern.
“Group 9” is the modern standard designation for this group, adopted by the IUPAC in 1990.In the older group naming systems, this group was combined with group 8 (iron, ruthenium, osmium, and hassium) and group 10 (nickel, palladium, platinum, and darmstadtium) and called group “VIIIB” in the Chemical Abstracts Service (CAS) “U.S. system”, or “VIII” in the old IUPAC (pre-1990) “European system” (and in Mendeleev’s original table).