The complex you mentioned, [Pt(NH3)4[PtI4], involves two platinum centers. In this case, it can be broken down into two parts: one platinum complex is coordinated to four ammonia (NH3) ligands, and the other platinum complex is coordinated to four iodide (I^-) ligands.
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[Pt(NH3)4]²⁺: This platinum center is typically in the +2 oxidation state and has a coordination number of 4 due to the four NH3 ligands. The geometry of this complex is tetrahedral.
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[PtI4]²⁻: This platinum center is likely in the +2 oxidation state (as well), coordinated to four iodide ions. With a coordination number of 4, the geometry here is also tetrahedral.
The overall geometry of the complex [Pt(NH3)4][PtI4] would therefore involve two tetrahedra connected in a way that they do not interfere with each other. It can be seen as a compound consisting of two tetrahedral entities linked through ionic interactions as it is a salt-like complex.
In summary, [Pt(NH3)4][PtI4] contains two tetrahedral geometries, one for each platinum complex.