Question

Write down the IUPAC name of the following complex:
$C{u_2}\left[ {Fe{{\left( {CN} \right)}_6}} \right]$

Answer 1

The names of compounds must be written according to IUPAC rules. There are some rules for writing the names of coordination complexes according to IUPAC. The complex must be categorized into two sections: positive and negative ions. After we write the name of the compound, we must write the metal's oxidation state in brackets.

Complete answer: The given coordination complex compound is $C{u_2}\left[ {Fe{{\left( {CN} \right)}_6}} \right]$
The complex must be divided into two parts as positive and negative ions based on the ions which are generated after adding the complex in water.
The given coordination complex compound splits into two ions in water which are $C{u^{2 + }}$ and ${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{4 - }}$
The metal which is present in the given coordination complex compound is iron or ferrous. Since the metal is present in the anion part, we should write it as ferrate.
Now, we have to find the oxidation state of the metal in $C{u_2}\left[ {Fe{{\left( {CN} \right)}_6}} \right]$
$x + 6\left( { - 1} \right) = - 4 \\\ \Rightarrow x = 6 - 4 \\\ \Rightarrow x = 2 \\\$
where $x$ represents the oxidation state of the metal iron and cyanide has a charge of $- 1$
Therefore, the oxidation state of iron or ferrous in the given coordination complex compound is $+ 2$.
The element cyanide $\left( {CN} \right)$ is present in the negative part of the compound, and hence it is called cyano. The number of cyanide ligands present is six, and so it is named Hexa.
Copper is present as a cation that has a positive charge of $+ 2$, so we can write the oxidation state of copper as $2$.
Therefore, the IUPAC name of the given coordination complex compound $C{u_2}\left[ {Fe{{\left( {CN} \right)}_6}} \right]$ is Copper $\left( {II} \right)$ hexacyanoferrate$\left( {II} \right)$

Note:
A coordination complex is the product of a Lewis acid-base reaction in which neutral molecules or anions (known as ligands) form coordinate covalent bonds with a central metal atom (or ion). Lewis bases are molecules that have at least one pair of electrons to donate to a metal atom or ion.