Copper(II), lead and zinc complexes of ethylenediamine-N,N'-diacetic acid.
From potentiometric measurements with glass and ion-specific electrodes, the formation constants of the complexes of ethylenediamine-N,N'-diacetic acid (EDDA, H(2)X) and Cu(2+), Pb(2+) and Zn(2+) have been determined at 25.0 degrees and ionic strength of 0.1 (NaNo(3)). The formation constants of the protonated species of EDDA were determined from separate measurements. The following species and log beta values were found (standard deviations in parentheses): HX(-) 9.17 (0.03); H(2)X 6.36 (0.02), H(3)X(+) 1.54 (0.16); CuX 17.47 (0.02); CuHX 20.87 (0.05); Cu(OH)X 6.34 (0.05); Cu(2)X 20.85 (0.14); PbX 11.71 (0.01); PbHX 15.60 (0.02); PbOHX 12.27 (0.02); Pb(2)X 15.02 (0.01); ZnX 11.71 (0.01); ZnHX 15.48 (0.03); Zn(OH)X 11.98 (0.03); Zn(2)X 14.91 (0.01). (Stepwise constants are given for HX(-), H(2)X and H(3)X(+).).
Schrøder
K H
KH
University of Trondheim Norges laererhøgskole Kjemisk institutt N-7000 Trondheim, Norway.
Johnsen
B G
BG