Table 1.

Protonation constants of MoO₄²⁻ and 8-HQA obtained by UV/Vis spectrophotometric titrations at T = 298.15 K and I = 0.2 mol·dm⁻³ in KCl_(aq).

p:q:r	log βpqr 1
1:0:1	3.97 ± 0.02
1:0:2	7.40 ± 0.02
0:1:1	9.55 ± 0.01
0:1:2	13.49 ± 0.02

¹ log β_pqr refer to equilibrium: p MoO₄²⁻ + q 8-HQA²⁻ + r H⁺ = (MoO₄)_p(8-HQA)_qH_r^{(2p+2q−r)−}; ±95% confidence interval.