A group, ion, or molecule coordinated to a central atom or molecule in a complex.
Ligand Definition. A ligand is an atom, ion, or molecule that donates or shares one or more of its electrons through a covalent bond with a central atom or ion. It is a complexing group in coordination chemistry that stabilizes the central atom and determines it reactivity. Medical Definition of LIGAND. : a group, ion, or molecule coordinated to a central atom or molecule in a complex. ADVERTISEMENT. Ligand. Definition. noun, plural: ligands. (1) A molecule, ion or atom bonded to the central metal atom of a coordination compound. (2) Any substance (e.g. hormone, drug, functional group, etc .) that binds specifically and reversibly to another chemical entity to form a larger complex. Supplement. A ligand may function as agonist or antagonist.
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define ligand