Q.What is linkage isomerism? Explain with an example.

Step 1. Linkage isomerism (Section 5.5.1.1) is a type of structural isomerism that arises when an AMBIDENTATE ligand -- one offering two different possible donor atoms -- is bonded to the central metal through one donor atom in one isomer and through the other donor atom in a second isomer.

Step 2. The formula, the metal, and every other ligand stay identical between the two isomers; only the identity of the bonded atom within the ambidentate ligand changes.

Step 3. The chapter's own example (Figure 5.3) uses the nitrite ion, NO₂⁻, bonded to Co³⁺: in [Co(NH₃)₅(NO₂)]²⁺ the nitrogen atom is the donor (the 'nitro' form), while in the isomeric [Co(NH₃)₅(ONO)]²⁺ one of the oxygen atoms is the donor instead (the 'nitrito' or ONO form). …

Define linkage isomerism as arising from an ambidentate ligand's choice of donor atom, and illustrate with the nitrite N-bound/O-boun …

• Confusing linkage isomerism (same ligand, different donor ATOM within it) with ionisation isomerism (an entirely different ligand/counter-ion swapped in from outside the coordination sphere). …