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) + aspartic acid and H(+) + aspartic acid have been determined in aqueous solution for 4 less than or equal to pH less than or equal to 9 at 25 degreesC and different ionic strengths ranging from (0.1 to 0.8) mol dm(-3) (NaClO(4)), using polarimetric, spectrophotometric, and potentiometric techniques. The composition of the complex was determined by the continuous variations method. It was shown that molybdenum(VI) forms a mononuelear 1:1 complex with aspartic acid of the type MoO(3)L(-2) at, pH = 5.8. The dependence of the protonation of aspartic acid and the stability constant of the complex on ionic strength is described by a Debye-Huckel-type equation, and finally the results have been compared with data previously reported.