Question

Which of the following pairs of isomers and types of isomerism are correctly matched?
(1) $\left[ Co \left( NH _{3}\right)_{5}\left( NO _{2}\right)\right] Cl _{2}$ and $\left[ Co \left( NH _{3}\right)_{5}( ONO )\right] Cl _{2}$ Linkage isomers
(2) $\left[ Cu \left( NH _{3}\right)_{4}\right] \left[ PtCl _{4}\right]$ and $\left[ Pt \left( NH _{3}\right)_{4}\right] \left[ CuCl _{4}\right]$ Co-ordinationIsomers
(3) $\left[Pt \left( NH _{3}\right)_{4} Cl _{2}\right] Br _{2}$ and $\left[Pt \left( NH _{3}\right)_{4} Br _{2}\right] Cl _{2}$ Ionisation Isomers
Select the correct answer using the codes given below:

• A. 1 and 2
• B. 2 and 3
• C. 1 and 3
• D. 1, 2 and 3

Answer 1

Answer: (D)

(i) The complexes $\left[ Co \left( NH _{3}\right)_{5}\left( NO _{2}\right)\right] Cl _{2}$ and $\left[ Co \left( NH _{3}\right)_{5}( ONO )\right] Cl _{2}$ exhibit linkage isomerism. This is because the nitro group is ambidentate ligand and has two donor atoms $N$ and $O$.
(ii) The complexes $\left[ Cu \left( NH _{3}\right)_{4}\right]\left[ PtCl _{4}\right]$ and $\left[ Pt \left( NH _{3}\right)_{4}\right]\left[ CuCl _{4}\right]$ exhibit coordination isomerism in which the ligands in the complex cation and the complex anion are interchanged.
(iii) The complexes $\left[ PtCl _{2}\left( NH _{3}\right)_{4}\right] Br _{2}$ and $\left[ PtBr _{2}\left( NH _{3}\right)_{4}\right] Cl _{2}$ are examples of ionization isomers as there is exchange of ions inside and outside the coordination sphere.