Cobalt group
Position in the periodic table
|
group | 9 |
period | |
4th |
27 Co |
5 |
45 Rh |
6th |
77 Ir |
7th |
109 m |
According to the inorganic nomenclature of the IUPAC, the elements of the 9th group are collectively referred to as the cobalt group of the periodic table .
The group contains the elements cobalt , rhodium , iridium and meitnerium . They are all heavy metals .
Meitnerium also belongs to the group of transuranic elements , a group name not included in the nomenclature.
In older representations of the periodic table, they were included in group VIIIA (IUPAC 1970) or VIIIB (Demming 1923). To avoid confusion, these older definitions should no longer be used.
Together with the platinum metals ruthenium , rhodium , palladium , osmium , iridium and platinum , the three metals iron, cobalt and nickel are also included in the nine-element iron-platinum group .