A speciation study of sulfur(iv) in aqueous solution

Abstract

In the current work ultraviolet spectrophotometric titrations at different S(iv) concentrations have been globally analysed using the entire spectral dataset to determine the complete speciation of S(iv) in aqueous solution over a large pH range (from 9.6 to 1). As a result, the dimerisation constant for the formation of disulfite from hydrogen sulfite has been accurately determined. Further, protonated disulfite has been identified and quantified for the first time. In addition, the molar absorptivities of all S(iv) species are also reported over the studied wavelength range.

Porous Capsules with a Large Number of Active Sites: Nucleation/Growth under Confined Conditions

“…When SO 2 is bubbled through an aqueous solution of 1 , the acetate ligands are displaced and two new capsules, 3 a and 4 a , are formed depending on the pH of the solution (see the Experimental Section). The incoming ligand could enter the capsule either as HSO 3 − , which is the dominant species in aqueous solutions of SO 2 at pH 5, or as SO 2 (aq), which is present in appreciable amounts at pH 1.5 14. Quite logically, lowering the pH results in a decrease in the number of sulfite ions taken up and in a reduced stability of the capsules, while oxomolybdenum fragments arising from their partial decomposition get trapped by the sulfite ligands (see below for details).…”

Experimental estimation of the bisulfite isomer quotient as a function of temperature: Implications for sulfur isotope fractionations in aqueous sulfite solutions

“…1052 cm À1 at 25°C; Connick et al, 1982 and references therein). By using the recent determination of the dimerization quotient at 25°C in low ionic strength media (Q d = 0.045 M À1 ; Beyad et al, 2014), we estimate a dimer concentration on the order of [S 2 O 5 2À ] $ 0.002-0.007 m in our solutions of [NaHSO 3 ] = 0.2-0.4 m (assuming negligible differences between molarity and molality). From previous Raman studies, other bands associated with S 2 O 5 2À may be expected within our measured spectral range at ca.…”

“…This simple picture is complicated by the more nuanced and somewhat uncertain molecular composition of bisulfite (HSO 3 À ), which may be comprised of two distinct isomers (Golding, 1960;Connick et al, 1982;Horner and Connick, 1986;Littlejohn et al, 1992;Risberg et al, 2007). Bisulfite compounds can also undergo reactions with each other to form a dimer (S 2 O 5 2À , HS 2 O 5 À ) when the overall HSO 3 À concentration is relatively high (Golding, 1960;Connick et al, 1982;Beyad et al, 2014). The two isomers of HSO 3 À differ in the structural site of protonation.…”

Kinetics of the autoxidation of sulfur(iv) co-catalyzed by peroxodisulfate and silver(i) ions

“…50,51 Hydrated sulfur dioxide is in equilibrium with hydrogensulfite ion with a pK a = 1.74 at 25.0°C:…”