What is the IUPAC name of the coordination compound ${\text{K}}_3[\text{Fe}(\text{CN}{)}_6]$?

Solution

1. The complex is ${\text{K}}_3[\text{Fe}(\text{CN}{)}_6]$.
2. The oxidation state of iron $x$ is calculated as $3(+1) + x + 6(-1) = 0$, which gives $x=+3$.
3. The ligand is cyano and the metal is in an anionic complex, so it is named ferrate.
4. Hence the answer is (B).