Among the following, the species having square planar geometry for central atom are 
i) XeF₄ 
ii) SF₄ 
iii) [NiCl₄]^–2 
iv) [PtCl₄]^–2

(i) In Xe​F₄, Xe under goes sp³d² hybridization and​ is square planar due to 2 lone pairs.

(iv) Pt has bigger d orbitals than Ni, which can hold more electron density because electron density can be spread out in a large d orbital. Therefore platinum can support a higher energy structure such as square planar structure.