what is ligands in chemistry

In chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The central metal atom is usually a metallic element, and the atoms and molecules used as ligands are almost always those that are capable of functioning as the electron-pair donor in the electron-pair bond formed with the metal atom. Ligands can be anions, cations, or neutral molecules, and they act as Lewis bases (electron pair donors), while the central atom acts as a Lewis acid (electron pair acceptor)/Coordination_Chemistry/Structure_and_Nomenclature_of_Coordination_Compounds/Ligands). The nature of bonding from metal to ligand varies from covalent bond to ionic bond. Ligands can be further characterized as monodentate, bidentate, tridentate, etc., depending on the number of binding sites with the central metal atom, charge, and size/Coordination_Chemistry/Structure_and_Nomenclature_of_Coordination_Compounds/Ligands). Some examples of ligands include water, ammonia, carbon monoxide, cyanide, chloride, and hydroxide.