Coordination compounds are chemical structures 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 complex. The arrangement and type of ligands influence the properties and reactivity of the compound. These compounds are significant in various fields, including biochemistry, where they play roles in processes like oxygen transport in hemoglobin. They are also important in catalysis, materials science, and the development of medications, showcasing their versatility in both nature and technology.