What is the Werner secondary valence in complex $[CoCl(NH_3)_5]^{2+} 2Cl^-$?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 6
In Werner’s theory:
- Primary valence = oxidation state
- Secondary valence = coordination number (number of ligands directly attached to the metal)
For the complex:
$[\text{CoCl}(\text{NH}_3)_5]^{2+}\, 2\text{Cl}^-$
Inside the coordination sphere, Co is bonded to:
- 5 NH₃ ligands
- 1 Cl⁻ ligand
Total ligands attached = 6