The carbon-donor ligand is one of the ligands. For carbon-donor ligands, the atoms, molecules and ions that bond with the central atom (metal or metalloid) should be included. C atoms，and electron electrons are provided by N atom.. Carbon-donor ligands are usually called referred to as carbene ligands and usually act as an electrically neutral singlet carbene. Carbene ligands feature highly electron donating properties that are often utilized in organocatalysts, ligands for organometallic complexes, and surface modifiers on metals. Common carbon donor ligands include CO, CS and CN.