Ionic strength dependence of formation constants: Complexation of Mo(VI) with aspartic acid

The formation constants of species formed in the systems H+ + Mo(VI) + aspa rtic acid and H+ + aspartic acid have been determined in aqueous solution f or 4 less than or equal to pH less than or equal to 9 at 25 degreesC and di fferent ionic strengths ranging from (0.1 to 0.8) mol dm(-3) (NaClO4), usin g polarimetric, spectrophotometric, and potentiometric techniques. The comp osition of the complex was determined by the continuous variations method. It was shown that molybdenum(VI) forms a mononuelear 1:1 complex with aspar tic acid of the type MoO3L-2 at, pH = 5.8. The dependence of the protonatio n of aspartic acid and the stability constant of the complex on ionic stren gth is described by a Debye-Huckel-type equation, and finally the results h ave been compared with data previously reported.