Lower sulfur oxides

The lower sulfur oxides are a group of inorganic compounds with the formula S_mO_n, where 2m > n. These species are often unstable and thus rarely encountered in everyday life. They are significant intermediates in the combustion of elemental sulfur.^[1] Some well characterized examples include sulfur monoxide (SO), its dimer S₂O₂, and a series of cyclic sulfur oxides, S_nO_x (x = 1, 2), based on cyclic S_n rings.

Interest in the lower sulfur oxides has increased because of the need to understand terrestrial atmospheric sulfur pollution and the finding that the extraterrestrial atmospheres of Io, one of Jupiter's moons, and Venus contain significant amounts of sulfur oxides. Some compounds reported by early workers such as the blue "sesquioxide", S₂O₃, formed by dissolving sulfur in liquid SO₃ appears to be a mixture of polysulfate salts of the S2+4 and S2+8 ions.^[1]