Chemical composition of venus clouds

From estimates of drying effect in the cloud layer, data of the Venera 14 X-ray fluorescent spectroscopy, and evaluation of photochemical production of sulfuric acid, it follows that sulfuric acid and/or products of its further conversion should constitute not only the Mode 2 particles but most of the Mode 3 particles as well. The eddy mixing coefficient equals 2 × 10 4 cm 2 s −1 in the cloud layer. The presence of ferric chloride in the cloud layer is indicated by the Venus u.v. absorption spectrum in the range of 3200–5000 Å, by the Venera 12 X-ray fluorescent spectrum, by the coincidence of the calculated FeCl 3 condensate density profile and that of the Mode 1 in the middle and lower cloud layer, as well as by the upward flux of FeCl 3 from the middle cloud layer which provides the necessary concentration of FeCl 3 in H 2SO 4 solution. FeCl 3 as the second absorber explains the localization of absorption in the upper cloud layer due to the FeCl 3 conversion to ferric sulfate near the boundary between the upper and middle cloud layers. Other possible absorbers such as sulfur, ammonium pyrosulfite, nitrosylsulfuric acid, etc. are discussed.