STUDIES ON THE CHROMOPHORIC REACTIONS OF MIXED POLYNUCLEAR COMPLEXES OF RARE EARTH-ARSENAZO Ⅲ-COPPERO-PHENANTHROLINE

摘要

In an acidic solution the mixed polynuclear complexes could be formed by association of rareearth-arsenazo Ⅲ complexing anions with copper o-phenanthrolinate cations.In this paper the formationconditions of lanthanum-arsenazo Ⅲ-copper-o-phenanthroline complex and its related reaction mechanismhave been studied in detail.The complex exhibits an absorption maximum at 663 nm and its apparent molarabsorptivity is found to be 1.22×105 L·mol-1·cm-1.The molar ratio of the components in the complex isestimated to be La:arsenazo Ⅲ:Cu:Phen=1:1:1:3.Its possible molecular formula can expressed as[Cu（Phen）3]（La-arsenazo Ⅲ）.The reaction is used to determine micro amounts of lanthanum（or rareearths）in copper containning synthetic samples and satisfactory results are obtained.