Question

$\left[\mathrm{Co}{\left({\mathrm{NH}}_{3_{}}\right)}_6\right]{\mathrm{Cl}}_3$What is primary valency according to Werner?

Answer 1

1. The concept is used in coordination compounds and is given by Werner's theory.
2. According to Werner's theory there are two types of valency: primary valency and secondary valency
3. The primary and secondary valencies are shown by the central metal atom of the coordination compound.
4. Primary valency is defined as the number of negative ions equivalent to the charge of a central metal ion.
5. Secondary valencies are defined as those valencies in which the number of ligands is attached to the metal ion.
6. Example: Hexammine cobalt(III) chloride $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_6\right]C{l}_3$, the total number of primary valencies is 3 because 3 Chloride ion is present, and so the oxidation number of $\mathrm{Co}\mathrm{is}3.$
7. Secondary valency is 6 as 6 Ammonia ligands are present and the coordination number of $\mathrm{Co}$ is 6.