The coordination geometry of an atom is the geometrical pattern formed by the coordination of ligands to a metal in a molecule or a coordination complex. The geometrical arrangement of the ligands vary according to the number and type of ligands bonded to the metal centre, and to the coordination preference of the metal. The coordination preference of a metal often varies with its oxidation state. The number of ligands can vary from two to eleven ligands per metal.
One of the most common coordination geometries is octahedral, where six ligands are coordinated to the metal in a symmetrical distribution, leading to the formation of an octahedron if lines were drawn between the ligands. Other common coordination geometries are tetrahedral and square planar.
Crystal field theory may be used to explain the relative stabilities of compounds of different coordination geometry, as well as the presence or absence of paramagnetism.
