Protonation and complex formation constants of 3-amino-1,2,4-triazole in NaCl and CaCl2 media at different temperatures and ionic strengths

Abstract The protonation of 3-amino-1,2,4-triazole was studied potentiometrically (glass electrode) in sodium chloride and calcium chloride solutions, 0.13 ⩽ I ⩽ 0.92 M , at 10, 25, 37 and 45°. The effect of the background electrolyte on the protonation constants is explained by a complex formation model. The species CaL + , CaHL 2+ and H 2 LCl (HL = 3-amino-1,2,4-triazole) are proposed. Stability constants, together with their dependence on temperature (Δ H °) and on ionic strength, are reported for the protonated and complex species.