Destructive distillation is the chemical process involving the decomposition of feedstock by heating it to a high temperature; the term generally applies to processing of organic material in the absence of air or in the presence of limited amounts of oxygen or other reagents, catalysts, or solvents, such as steam or phenols. It is an application of pyrolysis. The process breaks up or 'cracks' large molecules. Coke, coal gas, gas carbon, coal tar, Buckminsterfullerene, ammonia liquor, and "coal oil" historically, are examples of commercial products of the destructive distillation of coal.