Question

What are the primary and secondary valencies of copper in Tetraammine copper ll sulphate?

Answer 1

Part1: Primary valency of Copper in Tetraammine copper ll sulphate

1. Primary valency of metal complexes is generally referred to as their oxidation number.
2. Ammonia is a neutral ligand which has no charge.
3. So the Oxidation state of ${\mathrm{NH}}_3$is 0.
4. Oxidation number of copper $\left[\mathrm{Cu}{\left({\mathrm{NH}}_3\right)}_4\right]S{O}_4$ is calculated as shown below.

$x+0\left(4\right)-2=0$

$x-2=0$

$x=2$

So by solving the oxidation number of Copper is 2.

So the primary valency of Copper is 2.

Part2: Secondary Valency of Copper in Tetraammine copper ll sulphate

1. Secondary valency in metal complexes are generally referred to as their coordination number.
2. Coordination number of metal is the number of ligands attached to the metal.
3. In Tetraammine copper ll sulphate, Copper is surrounded by four amino groups (${\mathrm{NH}}_3$). So the coordination number of Copper is 4.

The secondary valency of Copper in tetraammine copper ll sulphate is 4.