Extraction of alkali metal, magnesium and calcium ions with cyclopentadienyltris(diethylphosphito-P)cobaltate(−1)

The extraction of lithium, sodium, potassium, magnesium and calcium ions with the oxygen tripod ligand cyclopentadienyltris (diethylphosphito-P)cobaltate(−1), [(C5H5)Co{P(O)(OC2H5)2}3]− has been studied as a function of pH and ligand concentration.Li+ could be successfully separated from Na+ and K+. The separation of Li+ from fCa2+ and Mg2+ was achieved by masking Mg2+ and Ca2+ with EDTA or by precipitating them with the ligand before Li extraction. The composition and stability constants have been determined for the complexes of Li+, Mg2+, and Ca2+.