Bridging ligand

A bridging ligand is an atom or a polyatomic entity that connects two or more metal centres in a complex. In naming a complex that includes a bridging ligand, the bridging ligand is preceded by "μ."

Virtually all ligands are known to bridge, with the exception of amines and ammonia. Particularly common bridging ligands are:
 * OH&minus;,
 * S2&minus;,
 * NH2&minus;
 * CO
 * Halides
 * Hydride
 * Thiolates and alkoxides
 * Cyanide

Polyfunctional ligands
Polyfunctional ligands can attach to metals in many ways and thus can bridge metals in diverse ways, including sharing of one atom or using several atoms. Examples of such polyatomic ligands are the oxoanions CO32&minus; and the related Carboxylate, PO43&minus;, and the polyoxometallates.