Compounds containing the carbonyl group, C=O. The term is commonly used in the restricted sense of aldehydes and ketones, although it actually includes carboxylic acids and derivatives. Metal carbonyls, in which carbon monoxide is a formal ligand., karbonüülrühma C=O sisaldavad ühendid: 1) orgaanilised ühendid–aldehüüdid, ketoonid ja karboksüülhapped ning nende derivaadid; 2)metallikarbonüülid, mille molekulides esineb süsinikmonooksiid ligandina