Editing Ammonium perchlorate (section)

==Decomposition==
Like most ammonium salts, ammonium perchlorate decomposes before [[melting]]. Mild heating results in production of [[hydrogen chloride]], [[nitrogen]], [[oxygen]], and water.

: 4 NH<sub>4</sub>ClO<sub>4</sub> → 4 HCl + 2 N<sub>2</sub> + 5 O<sub>2</sub> + 6 H<sub>2</sub>O

The combustion of AP is quite complex and is widely studied. AP crystals decompose before melting, even though a thin liquid layer has been observed on crystal surfaces during high-pressure combustion processes.<ref>{{cite journal | last1 = Boggs | first1 = T. L. | year = 1970 | title = Deflagration Rate, Surface Structure and Subsurface Profile of Self-Deflagrating Single Crystals of Ammonium Perchlorate | journal = AIAA Journal | volume = 8 | issue = 5| pages = 867–873 | doi=10.2514/3.5780| bibcode = 1970AIAAJ...8..867B }}</ref> Strong heating may lead to [[explosion]]s. Complete reactions leave no residue. Pure crystals cannot sustain a flame below the pressure of 2 [[Pascal (unit)|MPa]].

AP is a Class 4 oxidizer (can undergo an explosive reaction) for particle sizes over 15 micrometres<ref>NFPA 400: Hazardous Materials Code, 2010</ref> and is classified as an explosive for particle sizes less than 15 micrometres.<ref>NFPA 495: Explosive Materials Code, 2010</ref><ref>"Development of an Enhanced Hazard Classification System for Oxidizers Research Project, Technical Report", Safety Engineering Laboratories, Inc., The Fire Protection Research Foundation, 13 April 2006</ref>