Possible isomers are (I) [Pt(NH3)4Cl2]Br2⇒GI=2 (II) [Pt(NH3)4Br2]Cl2⇒GI=2 (III) [Pt(NH3)4BrCl] Br.Cl ⇒ GI. =3 I, II, III are ionisation isomers of given complex and each exhibits two geometrical isomers. Therefore total possible isomers will be 6 .
