Weathering release occurs of Ca and other ions into surface waters. Rainfall is acidic because atmospheric carbon dioxide dissolves in the rainwater producing weak carbonic acid. In unpolluted environments, the rainfall pH is around 5.6. Acid rain occurs when gases such as sulfur dioxide and nitrogen oxides are present in the atmosphere. These oxides react in the rain water to produce stronger acids and can lower the pH to 4.5 or even 3.0. Sulfur dioxide, SO, comes from volcanic eruptions or from fossil fuels, can become sulfuric acid within rainwater, which can cause solution weathering to the rocks on which it
Lower sulfur oxides Jupiter's moons, and Venus contain significant amounts of sulfur oxides. Some compounds reported by early workers such as the blue "sesquioxide", SO, formed by dissolving sulfur in liquid SO appears to be a mixture of polysulfate salts of the S and S ions. These species are all very unstable and are observed as fleeting intermediates in the gas phase. At a few millibars pressure, the relative stabilities are SO > SO > SO. Sulfur monoxide (SO) and its dimer (SO) have been trapped at low temperature. Disulfur dioxide (SO) is a dimer of sulfur monoxide. It has C structure (planar).