Sources of organic matter and inorganic tracers on Jupiter, including solar UV pbotolysis, lightning discharges, and convective quenching of hot gases from the lower atmosphere, are reviewed in light of Earth-based and Voyager data with the purpose of predicting the tropospheric steady-state abundances and vertical distributions of HCN, CH20 , and other species.It is concluded that a steady-state mole fraction of HCN in the Jovian troposphere of only ~ 10-a2 could be maintained by vertical transport of hot gases from the deep atmosphere. The observed HCN abundance (roughly Xnc N = 10-9) appears to be due to photochemical reactions.After HCN, the most abundant organic disequilibrium species in the troposphere is probably C2H6, derived from direct photolysis of CH 4 at high altitudes, with a mole fracton of ~ 10-1o at the H20 cloud level. Inorganic tracers of disequilibrium processes are also briefly summarized.

No abstract

No abstract

A critical assessment of thermal and equilibrium data for silicon oxynitride (Si2N20) is presented. Selected values for the heat of formation of Si2N20 from the elements and the absolute entropy of S i 2 N 2 0 at 298.15 K are A&& = -947.7 ? 5.4 Wlmol and S& = 45.35 ? 0.4 Jlmol -K, respectively. A table of thermodynamicfunctions for Si2N20from 298 to 2500 K , which has been calculated from the analysis of the literature data, is also presented. ACK of thermodynamic data has hin-

No abstract