Which of the following complexes has a square planar geometry and exhibits geometrical isomerism?

Step-by-step solution

For [ Ni ( CO )₄] , Ni is in 0 oxidation state ( 3d¹⁰ configuration after pairing). It undergoes sp^3 hybridization, forming a tetrahedral geometry. Tetrahedral complexes do not show geometrical isomerism. For [ Pd ( en )₂]²⁺ , Pd is in +2 oxidation state. Being a 4d series element, it forms a square planar complex ( dsp^2 hybridization). However, since ethylenediamine (en) is a symmetrical bidentate ligand, the complex is of the type [M(AA)₂] , which does not exhibit geometrical isomerism. For [ Pt ( NH ₃)₂ Cl ₂]