The total number of possible isomers for Pt NH 3 4 Cl 2 Br 2 is___.

$\left[\mathrm{Pt}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]{\mathrm{Br}}_2$, $\left[\mathrm{Pt}{\left({\mathrm{NH}}_3\right)}_4\mathrm{ClBr}\right]\mathrm{BrCl}$ and $\left[\mathrm{Pt}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Br}}_2\right]{\mathrm{Cl}}_2$ are the ionisation isomers and each isomer exhibits geometrical isomerism.

Hence, total number of isomers $=6$.