Acid rain Acid rain Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals and infrastructure. Acid rain is caused by emissions of sulphur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids. Some governments have made efforts since the 1970s to reduce the release of sulphur dioxide and nitrogen oxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightning strikes, and sulphur dioxide
Lower sulfur oxides Disulfur monoxide (SO) is an unstable analogue of sulfur dioxide. Like SO as well as ozone (O), and trisulfur (S), it adopts a bent structure. The S-S bond length is 188.4pm, the S-O bond is 146.5pm and the SSO angle is 117.88. The two dipole moment components are μa = 0.875D and μb = 1.18D This species decomposes to give a polymeric sulfur oxides ("PSO's") with the approximate formula [SO]. PSO's decompose at room temperature to elemental sulfur and SO. PSO's have been proposed to be responsible for the colour of Io. Trisulfur monoxide, SO is an unstable molecule. It