“…Ser., No. Extensive study has been made within the past 10 years concerning the interaction of organophosphorus compounds with metal salts. Most is known and most work has been done with phosphine oxide ligands (6-10), whereas the phosphate esters have been studied primarily as extractants for various metal ions from solution (11)(12)(13). Less is known about the intermediate phosphoryl compounds, the phosphonate and phosphinate esters (14)(15)(16)(17).…”