Question

What is the geometry of an `ML_2X_2` complex?

Answer 1

A four coordinate metal complex can have either square planar OR tetrahedral geometry.

Explanation:

If `ML_2X_2` is tetrahedral, all the metal ligand positions are equivalent. Should the complex be square planar, the chelating oxalato ligand can ONLY span cis -positions, to give a cis metal complex. For the trans complex, the oxalato ligand would join up metal centres (with the elimination of `AgCl`!) to give oligomers and polymers.