 Another important application of samarium and its compounds is as catalyst and chemical reagent . Samarium catalysts assist decomposition of plastics , <unk> of pollutants such as polychlorinated biphenyls ( PCBs ) , as well as the dehydration and dehydrogenation of ethanol . Samarium ( III ) triflate ( Sm ( <unk> ) 3 , that is Sm ( <unk> ) 3 ) , is one of the most efficient Lewis acid catalysts for a halogen @-@ promoted Friedel – Crafts reaction with alkenes . Samarium ( II ) iodide is a very common reducing and coupling agent in organic synthesis , for example in the <unk> reactions ; <unk> ; Danishefsky , <unk> , <unk> and Holton Taxol total syntheses ; strychnine total synthesis ; Barbier reaction and other reductions with samarium ( II ) iodide . 
