What is square planar?

In chemistry, a square planar molecular geometry describes the shape of compounds where a central atom is surrounded by four atoms at the corners of a square. The central atom is typically a transition metal, such as platinum or palladium, which can form coordination complexes with ligands.

Square planar complexes are characterized by bond angles of 90 degrees between the ligands and the central atom. The geometry is often observed in compounds with a metal bonded to four ligands of the same type, such as in [MX4]2- species.

The square planar geometry is typically more stable when the ligands are large and have a high degree of steric hindrance, preventing the formation of other geometries such as tetrahedral or octahedral.

Overall, square planar geometry is common in transition metal complexes and can have important implications for the reactivity and properties of the molecules.