in a co ordinate compound where both anion and cation are complex , how to decide that which species will aquire positive or negative charge on decomposition? let in K4Fe(CN)6 we know that k ion aquire + charge & other will -. but in [Pt(CN)4][Pt(Cl)4]. please answer.

Acomplex ion can be defined ion which consists of a central metal cation to which several anions or molecules are bonded.Now this complex ion may be positively or negatively charged.The metal cation is called thecentral atom,and the attached anions and molecules are calledligands.A neutral species containing a complex ion is called acoordination compound. These compounds usually have complicated formulas.For examples:-[Ag(NH3)2]Cl and K3[Fe(CN)6].Here the complex ion is shown enclosed in brackets. In the silver compound, Cl–is a free (meaning uncomplexed) chloride ion, and in the iron compound each K+is a free potassium ion. K+and Cl–ions in the above formulas are examples ofcounter ions. They serve to balance or neutralize the charge of the complex ion.
One can identify the species which acquire positive charge or which negative by the given complex.Cations are formed by metals and anions by non-metals.In K4[Fe(CN)6],K+ will acquire the positive and the complex will have negative charge.Now in [Ni(H2O)6]Cl2 the Cl being non-metal will have negative charge and thus the complex on the other hand will have positive charge.Metals occupy left side of the periodic table and non-metal on the right side.So by looking the complex you can identify the positive or negative species formed on decomposition.