Outer-sphere association constants of cobalt(III) ammines and acidoammines with phosphorus(V) in aqueous solution

Electronic spectra of aqueous solutions in the range of 230-350 nm were measured to study the association of cations [CO(NH3)(5)C2O4](+) [CO(NH3)(5)SO4](+), [CO(NH3)(5)OH](2+), [Co(NH3)(5)NO2](2+), [Co(NH3)(6)](3+), and [Coen(3)](3+) with H2PO4-, HPO42-, PO43-, P3O93-, P2O74-, and P4O124- anions. The first association constants beta (0)(1) of the specified cations with the specified anions at I --> 0 and 25 degreesC were determined. An equation log beta (0)(1) = AZ(+) + B, where Z(+) is the charge of a cobalt(III) complex and A and B are constants, quantifies all of the association constants found.