Thermal decomposition
（重定向自Thermal degradation）
![Equipment used by Priestley in his experiments on gases](/Images/godic/202502/16/Priestley_Joseph_pneumatic_trough2116.jpg")
- For the biological process, see decomposition.
Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes.
The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. If decomposition is sufficiently exothermic, a positive feedback loop is created producing thermal runaway and possibly an explosion.