Prussic acid, also known as hydrogen cyanide, is a colorless and highly toxic compound that has a distinct odor of bitter almonds. Due to its high toxicity, it is used in a variety of industrial processes and as a chemical weapon. Some synonyms for prussic acid include hydrocyanic acid, cyanide, and formonitrile. In addition to being used in industrial processes, prussic acid is also found naturally in some fruits, such as cherries and apples. It is important to exercise caution when working with or near prussic acid, as exposure to even small amounts can be fatal.