complex formation
Quick Summary
In chemistry, a complex is a substance, either an ion or a neutral molecule, formed by the union of simpler substances. These are held together by chemical forces, not physical ones, and their formation significantly impacts solution behavior.1
A common type is the coordination complex, which features a central metal atom or ion bonded to surrounding ions, groups, or molecules. These surrounding entities are called ligands, and they act as electron-pair donors in forming coordinate covalent bonds with the central metal atom, which acts as an electron-pair acceptor. Examples of ligands include water, ammonia, and cyanide ions.234
Complex formation is a type of Lewis acid-base reaction. These complexes have diverse applications, including use as dyes and pigments, in metal extraction and purification, and in analytical chemistry. They are also central to understanding chemical bonding in transition metals and play roles in catalysis and oxidation-reduction reactions.456
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