Question

The co-ordination complex ions $[Co(NH_3)_5(NO_2)]^{2+}$ and $[Co(NH_3)_5(ONO)]^{2+}$ are ________ of each other.

• A. ionization isomers
• B. solvate isomers
• C. linkage isomers
• D. co-ordination isomers

Hint:

Look for ligands like $NO_2^-/ONO^-$, $SCN^-/NCS^-$, or $CN^-/NC^-$ to quickly identify linkage isomerism.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Isomerism in coordination compounds arises when compounds have the same molecular formula but different arrangements of atoms.
Step 2: Detailed Explanation:
Linkage isomerism occurs when an ambidentate ligand is present in the complex.
An ambidentate ligand is a ligand that has more than one donor atom but coordinates through only one atom at a time.
In the given complexes, the ligand is the nitrite ion ($NO_2^-$).
1. In $[Co(NH_3)_5(NO_2)]^{2+}$, the ligand is bonded through the Nitrogen atom (nitro-N).
2. In $[Co(NH_3)_5(ONO)]^{2+}$, the ligand is bonded through the Oxygen atom (nitrito-O).
Since the difference is in the mode of attachment (linkage) of the ligand to the metal, they are linkage isomers.
Step 3: Final Answer:
They are linkage isomers.