zero-oxidation-state metal carbonyl

Zero-oxidation-state metal carbonyls are chemical compounds where a metal atom is bonded to carbon monoxide (CO) ligands, and the metal itself has an oxidation state of zero. This is distinct from simple inorganic compounds where metals typically have positive oxidation states.1

These compounds are formed by reacting finely divided metals with carbon monoxide. A notable example is tetracarbonylnickel, Ni(CO)₄, discovered by Ludwig Mond, which is highly volatile and toxic.213

Metal carbonyls are valuable in chemistry because they are often soluble in organic solvents and are reactive, making them useful starting materials for synthesizing compounds with metals in zero or low oxidation states. They also play roles in industrial processes, such as refining metals and acting as catalysts in chemical synthesis.13