Potentiometric study of reactions of titanium complexes in phosphate-perchlorate acid solutions

The potentiometric method is used to measure the equilibrium potential in t he Ti(IV)/Ti(III) system and determine that monophosphate Ti(IV) complexes and Ti3+ hydrated complexes dominate in phosphate-perchlorate acid solution s, 4M(H, Na)ClO4, at c(H3PO4) of 5 X 10(-2) to 4 x 10(-1) M. Equations that describe the total electrode reaction are proposed. Decreasing the concent ration of free hydrogen ions from 3 to 0.12 M results in the deprotonation of TiO(H2PO4)(+) complexes and the formation of TiO(HPO4) complexes. Equili brium constants for reactions of the formation of Ti(IV) monophosphate comp lexes and the protonation of TiO(HPO4) complex are calculated.