Complexation of Tungsten(VI) with D-(−)-Quinic Acid at Different Ionic Strengths

Job’s method of continuous variations was applied for the determination of the tungsten(VI) to D-(−)-quinic acid {(1 R ,3 R ,4 S ,5 R )-(−)-1,3,4,5-tetrahydroxycyclohexane-1-carboxylic acid} molar ratio in its complex, which is 1:1 at pH 7.50. This paper aims to study the solution equilibria between tungsten(VI) and the ligand at different ionic strengths ranging from (0.1 to 1.0) mol·dm −3 of sodium chloride at T = 298 K. Three models based on the Debye–Hückel equation were investigated for the description of the ionic strength dependence of the stability and dissociation constants. Finally, the stability constant values were compared with the literature data and interpreted on the basis of these ionic strength dependent models.