 Alfred Werner , a Nobel @-@ prize winning pioneer in coordination chemistry , worked with compounds of empirical formula [ Co ( NH3 ) 6 ] Cl3 . One of the isomers determined was cobalt ( III ) hexammine chloride . This coordination complex , a typical Werner @-@ type complex , consists of a central cobalt atom coordinated by six ammine orthogonal ligands and three chloride counteranions . Using chelating ethylenediamine ligands in place of ammonia gives tris ( ethylenediamine ) cobalt ( III ) chloride ( [ Co ( en ) 3 ] Cl3 ) , which was one of the first coordination complexes to be resolved into optical isomers . The complex exists in the right- and left @-@ handed forms of a " three @-@ bladed propeller " . This complex was first isolated by Werner as yellow @-@ gold needle @-@ like crystals . 
