Chloropicrin is a slightly oily, colorless liquid of the formula CCl3NO2. The vapor is highly poisonous if inhaled, and is used for military purposes as a poison gas, in organic synthesis, in fumigants, in fungicides and insecticides, and for the extermination of rats. Chloropicrin is a relatively stable liquid that is prepared by the reaction of picric acid with calcium hypochlorite or by the addition of nitrogen to chlorinated hydrocarbons.