 Europium compounds tend to exist trivalent oxidation state under most conditions . Commonly these compounds feature Eu ( III ) bound by 6 – 9 oxygenic ligands , typically water . These compounds , the chlorides , sulfates , nitrates , are soluble in water or polar organic solvent . Lipophilic europium complexes often feature acetylacetonate @-@ like ligands , e.g. , Eufod . 
