Stability constants of certain lanthanide(III) and actinide(III) chloride and nitrate complexes

Abstract

By means of acid-dependency studies, the extractant di[para(1,1,3,3-tetramethylbutyl)phenyl] phosphoric acid, HDOΦP, in toluene as a carrier diluent has been shown to extract M(III) lanthanides and actinides from aqueous perchlorate, chloride and nitrate media as species containing none of the anions present in the aqueous phase. Consequently, extraction of M(III) lanthanides and actinides from mixed perchlorate-chloride and from mixed perchlorate-nitrate aqueous phases may be used to determine the stability constant, k c , for MCl 2+ and M(NO 3) 2+. The k c values, at 22±1° C, μ = 1·0, so determined are: MCl 2+, La(0·9 ± 0·3), Ce(0·9 ± 0·3), Pr(0·9 ± 0·3), Eu(0·9 ± 0·3), Tm(0·8 ± 0·3), Yb(0·6 ± 0·2), Lu(0·4 ± 0·2), Am(0·9 ± 0·2); M(NO 3) 2+, La(1·3 ± 0·3), Ce(1·3 ± 0·3), Pr(1·7 ± 0·3),Eu(2·0 ± 0·3), Tm(0·7 ± 0·2), Yb(0·6 ± 0·2), Lu(0·6 ± 0·2), Am(1·8 ± 0·3).