Acidic oxide Some non-metal oxides, such as nitrous oxide (NO) and carbon monoxide (CO), do not display any acid/base characteristics. Acidic oxides can also react with basic oxides to produce salts of oxoanions: Acidic oxides are environmentally relevant. Sulfur and nitrogen oxides are considered air pollutants as they react with atmospheric water vapour to produce acid rain. Although it is difficult to classify these oxides as acids, the property is manifest in reactions with bases. For example, carbon dioxide reacts with alkali. For this reason, alkali is kept in stoppered vessels to inhibit reaction with atmospheric carbon dioxide. In geochemistry complex silicates
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).