Question

IUPAC name for ${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{ - 4}}$ is?
A.Hexacyanoferrate $\left( {II} \right)$
B.Hexacyanoiron $\left( {II} \right)$
C.Hexacyanoferrate $\left( {IV} \right)$
D.Hexacyanoferrate $\left( {II} \right)$ ion

Answer 1

Complex compound names can be written based on the rules related to IUPAC nomenclature of complex compounds. When a coordination sphere consists of negative charge the metal atom should end with -ate and as the charge is mentioned on the coordination sphere the complex should be written as ion.

Complete answer:
Complex compounds were also known as coordination compounds. Coordination compounds are special properties containing compounds. These compounds can retain or does not lose their identity when dissolved in water or any other organic solvents.
Given complex is ${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{ - 4}}$ it consists of a central metal atom of iron, and the ligand is cyanide. Cyanide is a strong ligand and carries the charge of $- 1$ .
The oxidation number of iron will be $x + 6\left( { - 1} \right) = - 4 \Rightarrow x = - 2$
Thus, the oxidation number of iron is $- 2$
The given complex is anionic as the charge mentioned on the coordination sphere is negative. So, the metal atom should end with -ate. As the charge is mentioned on the coordination sphere, the name of the complex should end with ion.
At first, the ligand number and name should be written followed by metal atoms with oxidation number in roman numerals within brackets.
Thus, the name of the given complex is Hexacyanoferrate $\left( {II} \right)$ ion
Option D is the correct one.

Note:
The charge on the coordination sphere must be observed whether it is anionic or cationic. If it is anionic the metal atom should end with -ate. Whether it is positive or negative charge on the coordination sphere the name of the complex should end with ion.