Coordinantes

Coordinantes is a term used in chemistry to describe atoms or groups that coordinate to a central atom, typically a metal ion, in a coordination complex. Coordinantes donate electron pairs to form coordinate covalent bonds, also known as dative bonds, and thereby stabilize the structure of the complex. In many languages the term coordinante or coordinantes is used interchangeably with ligand, though usage varies by tradition and field.

Coordinantes can be monodentate, donating a single pair of electrons from one atom, or polydentate, providing multiple donor atoms that can clasp the central atom more than once. The number of coordinating donor atoms around the central atom determines the coordination number and often the geometry of the complex, such as octahedral or tetrahedral arrangements. Common coordinantes include water, ammonia, chloride, and cyanide, while polydentate examples include ethylenediamine and oxalate. In many well-known complexes, several coordinantes collectively fill the coordination sphere of the metal center.

While the term coordinante appears in some older or non-English literature, the modern and widely used term in English is ligand. Coordinantes are nonetheless conceptually identical to ligands: they are electron-pair donors that bond to a central atom to form coordination compounds. The distinction is mostly terminological rather than structural.

See also: ligand, coordination chemistry, coordination complex, chelation, dative bond.