Vanadium(V) equilibria. Spectrophotometric and enthalpimetric investigation of the dimerization and deprotonation of HVO42-
The dimerization and deprotonation of HVO42- have been investigated in 1 M Na(Cl) medium at 25°C. Spectrophotometric and calorimetric measurements were made at [OH-] ≥, 0.05 M, where all other vanadate(V) hydrolysis equilibria could be neglected. Equilibrium constants and other thermodynamic quantities have been determined: for the dimerization of HVO42- log Kd = 0.83, ΔH0 = -28 kJ mol-1 and TΔS0 -24 kJ mol-1, and for the ionization log K = - 13.29, ΔH0 24 kJ mol-1 and TΔS0 = -52 kJ mol-1. © 1991.