The Reaction of H₂S with SO₂: Molecular Structures, Energies, and Vibrational Data of Seven Isomeric Forms of H₂S₃O

Abstract

High-level a b initio MO calculations (MP2/6-31 lG**//MP2/6-31 lG**) on 16 isomeric forms of H,S,O (including rotamers) have been performed. The nonhelical hydroxotrisulfane HOSSSH 1 a (motif + + -) is the most stable isomer, while the chains with motifs + + + and + -+ are less stable by 1.7 and 3.7 kJmol-', respectively. The other isomers of H,S,O increase in energy in the order HSS(0)SH < HOS(S)SH < HSOSSH < HS(0)SSH < HS(S)SOH < HS(S)OSH.The trisulfane-2-oxide

Acidity constants of some sulfur oxoacids in aqueous solution using CCSD and MP2 methods

“…1 shows the optimized structures of the selected acids in the gas phase. As mentioned before, there are several isomers for each sulfur oxoacid (neutral, mono-and dianion) [15][16][17][18][19][20][21][22]35,36 and the most stable isomer (lowest Gibbs free energy) for each species was selected for the geometry optimization in this work. For example, Steudel and Otto 18 have studied the stabilities of different isomers for H 2 S 2 O 3 and H 2 SO 5 along with their monoanions in the gas phase.…”

Theoretical study on the reactivity of sulfate species with hydrocarbons

“…For example, aqueous calcium sulfate (CaSO 4 ) was observed to have the slowest rate of reduction, followed by calcium sulfite (CaSO 3 ), and then by elemental sulfur (S 8 ) as the most reactive . Depending on the pH conditions of the environment, sulfur in the S(IV) state also occurs as SO 2 , and previous theoretical studies have identified a reaction mechanism for the reduction of SO 2 (S(VI)) to S 8 (S(0)) with a maximum energy barrier of only $36.5 kcal mol À1 (Drozdova and Steudel, 1995;Sendt and Haynes, 2005). These results indicate that the reduction of S(VI) to S(IV) is likely to be the rate limiting step in the overall pathway of reduction of sulfate to sulfide.…”

The Gas Phase Acidities of the Sulfanes H2Sn (n = 1–4)

“…Derivatives of the sulfanes like the sulfane oxides HϪSϪSϪOH [28] and HϪSϪS(O)ϪSϪH [29] will probably be similarly strong acids in the vapor phase. Therefore, the dissociation of H 2 S 2 requires much less Gibbs free energy than that of H 2 S and the dissociation of H 2 S 3 requires less than that of H 2 S 2 and so forth.…”