Nitric Oxide may be produced in the atmosphere of Venus by lightning storms in the clouds. Here we suggest that the odd nitrogen thus formed may play an important part in the chemistry of the clouds. Specifically, we estimate production rates for NO2 in the limiting case of high NO concentrations. If the NO density is high we suggest that NO2 may catalyse the production of sulfuric acid aerosol from sulfur dioxide and water vapor, and may also form nitrogen--sulfur compounds such as nitrosyl sulfuric acid, NOHSO4. The ''large particles'' seen by the Pioneer Venus sounder probe may contain considerable quantities of NOHSO4. If this is the case odd nitrogen must be present in the atmosphere in at least a parts-per-million mixing ratio.