The primary and secondary valencies of cobalt respectively in Co ( NH 3 ) 5 Cl Cl 2 are:

$\left[\mathrm{Co}({\mathrm{NH}}_3{)}_5\mathrm{Cl}\right]{\mathrm{Cl}}_2$

The primary valency is the ionisable valency.  Oxidation number of $\mathrm{Co}$ is $+3$. So, primary valency is $3$. Secondary valency refers the coordination number. It is an octahedral complex so, secondary valency is 6.