Question

Which of the following is an example of a homoleptic complex?
A. $[Co{{(N{{H}_{3}})}_{6}}]C{{l}_{3}}$
B. $[Pt{{(N{{H}_{3}})}_{2}}C{{l}_{2}}]$
C. $[Co{{(N{{H}_{3}})}_{4}}C{{l}_{2}}]$
D. $[Co{{(N{{H}_{3}})}_{5}}Cl]C{{l}_{2}}$

Answer 1

Hint : Think about what the word ‘homoleptic’ means. A clue towards it is the suffix ‘homo-’ which means ‘of the same kind’.

Complete step by step solution :
A homoleptic complex is a coordinate compound in which all the ligands that are bonded to the central atom are of the same species.
The central atom and the surrounding ligands are included in the coordination sphere. This coordination sphere is denoted by being enclosed in square brackets [ ].
There is only one central metallic atom included in the coordination sphere, all the other non-metallic entities should be considered as ligands.
Among the options given we have to choose the one that has only one type of ligand enclosed in the square brackets.
All the options except ‘A. $[Co{{(N{{H}_{3}})}_{6}}]C{{l}_{3}}$’ have both $N{{H}_{3}}$ and $Cl$ as ligands in the coordination sphere.

Hence, the correct option is ‘A. $[Co{{(N{{H}_{3}})}_{6}}]C{{l}_{3}}$’.

Additional Information:
The class of compounds that have more than one type of ligand attached to the central metal atom are known as heteroleptic complexes.
These coordination compounds may look complicated but are found all around us. The vitamin ${{B}_{12}}$, haemoglobin, chlorophyll, and other complex dyes are all coordination compounds.

Note : Please do not confuse the definition of homoleptic complexes as ‘Coordination compounds that have the same ligands both inside and outside the coordination sphere’ instead of ‘Coordination compounds having only one type of ligand attached to the central metal atom