The synergism found with combinations of mixed metals with organic phosphites is complex. Phosphite esters are well known as antioxidants and antioxidant synergists in many polymers and, no doubt, function in this regard in PVC. Their initial use, however, was to complex insoluble metal chlorides, improving clarity [47].Thus,They are still spoken of as “chelators.'' It is clear that they complex metal stabilizer salts as well, improving their efficiency through increased compatibility and probably assisting in the displacement reaction. This may be to the extent of actually contributing ligands via the Arbuzov reaction[48].