Coordination sphere

Definition

The coordination sphere includes the central metal atom or ion and its directly attached ligands, enclosed in square brackets. It defines the immediate chemical environment of the central atom in a complex.

5 Must Know Facts For Your Next Test

1. The coordination sphere is represented by square brackets in chemical formulas.
2. Ligands inside the coordination sphere are directly bonded to the central metal ion.
3. Ions or molecules outside the square brackets are not considered part of the coordination sphere but can be counter-ions.
4. The properties and reactivity of a coordination compound significantly depend on its coordination sphere.
5. Chelating ligands can form more stable complexes by occupying multiple positions within the coordination sphere.

Related terms

Ligand:

A molecule or ion that donates a pair of electrons to a central metal atom or ion to form a coordinate bond.

Chelate: A complex where a ligand forms multiple bonds with a single central metal ion, increasing stability.

Coordination Number:

The number of ligand donor atoms bonded to the central metal ion in a complex.