Structures of the ethylenediaminetetra-acetate complexes of some bivalent cations in aqueous solution

Abstract

The stability constants for mixed complex formation in aqueous solution between certain metal–EDTA complexes and various unidentate ligands have been obtained from spectrophotometric measurements. The results can be interpreted to obtain the proprotion of a parent metal–EDTA complex which is sexidentate, the remaining part being aquoquinquedentate. Proportions of EDTA complexes in the sexidentate form at 25·0° and l= 1·00M are cobalt(II), 76%; nickel(II), 75%; copper(II), 62%; and lead(II), ca. 70%.