Question

Explain the following giving an example in each case:

(i) Linkage isomerism

(ii) An outer orbital complex

(iii) A bidentate ligand

Answer 1

(i) Linkage isomerism: The isomers which have same molecular formula but differ in the linkage of ligand atom to the central metal atom are called linkage isomers, e.g., [Co(NH₃ )₅ NO₂ ]Cl₂ and [Co(NH₃)5ONO]Cl₂ Pentaamminenitrito–N–Cobalt (III) chloride pentaamminenitrito–O–Cobalt (III) chloride

(ii) Outer orbital complex: When ns, np and nd orbitals are involved in hybridisation, outer orbital complex is formed, e.g., [CoF₆ ]^2- in which cobalt is sp³ d² hybridised.

(iii) Bidentate ligand: When a ligand is bound to a metal ion through two donor atoms it is said to be bidentate ligand, e.g., H₂N—CH₂ —CH₂ —NH₂ (ethane–1, 2–diamine, C₂ O^2-₄  (oxalate), etc.