A coordination complex is a chemical structure formed by a central metal atom or ion bonded to surrounding molecules or ions, known as ligands. These ligands can be neutral molecules or charged ions that donate electron pairs to the metal, creating a stable arrangement. Coordination complexes are important in various fields, including bioinorganic chemistry, catalysis, and materials science. The properties of coordination complexes depend on the type of metal and ligands involved, as well as their arrangement in space. Common examples include hemoglobin, which transports oxygen in the blood, and copper sulfate, used in agriculture. Understanding these complexes helps in designing new materials and catalysts.