Different theoretical levels of theory including B3LYP/6-311+G(3df,3pd), MP2/6-311+G(3df,3pd), QCISD/6-311+G(d,p), CBS-QB3 and CCSD(T)/6-311+(d,p)//B3LYP/6-311+G(3df,3pd) have been employed to determine the structures, relative stabilities, electronic properties and thermochemistry of the selected S2O52- isomers in the gas phase and aqueous solution. Atoms in molecules (AIM) method and natural bonding orbital (NBO) were used to characterize the origin of atomic bonds. The NBO and AIM calculations showed that the strength of S-O and S-S bonds in the (O3SSO2)2-, (O2SOSO2)2- and (OSOSO3)2- isomer are relatively weak and go toward dissociation to form , SO3-SO2-, SO- and SO4- radical anions. For more confirmation, the dissociation equilibrium constant (K diss) of each isomer were calculated at 298K and showed that by increasing the dielectric constant of the solvent, the stability of the S2O2/5- isomer increases. Based on these result, the isomers are considerably unstable and dissociate in the gas phase compared with solution.
- Relative stability
- S2O52- isomers