Theoretical studies of sulfite – sulfur dioxide clusters, SO32−(SO2)n: structure and stability of SnO2n+1 anions, n = 1–5

Abstract

Density functional calculations using the B3PW91 functional with the 6-311+G(3df) basis set were performed on the addition of n = 1–4 SO2 molecules to SO3− and SO32−. Geometry optimizations were performed for a large number of possible structures. At n = 4, the dianionic cluster becomes adiabatically more stable than the monoanionic one, with an adiabatic electron detachment energy of 0.30 eV. Monoanionic clusters are characterized by the O–S–O–SO3 moiety having long O–S bonds to SO2 molecules. Dianionic clusters, however, prefer S–S bonding of O3S–O–S(O) with SO2.