Ammonium perchlorate (AP) is a chemical compound with the formula NH₄ClO₄. It is the salt of ammonia and perchloric acid. Like other perchlorates, it is a powerful oxidizer.

It is produced by reaction between ammonia and perchloric acid, or by double decomposition between an ammonium salt and sodium perchlorate.

It crystallises in colorless rhombohedra with a relative density of 1.95. Like most ammonium salts, it decomposes before melting. Mild heating results in chlorine, nitrogen, oxygen and water, while strong heating may lead to explosions.

The combustion of such compound is quite complex and is widely studied in literature. Ammonium perchlorate crystals decompose before melting, even though a thin liquid layer has been observed on crystal surface during high pressure combustion processes._[3]

The gaseous decomposition products are in general ammonia- and chlorine-based and can react together generating a thin premixed flame very close to the crystal surface. Pure crystals cannot sustain a flame below the pressure of 20 bar (2 MPa). Nevertheless, the material is considered hazardous if ground under 15 micrometres. When AP is mixed with a fuel (like a metal powder or mixed with a polymeric binder) it can generate self-sustained combustion also far under atmospheric pressure

As an oxidizer, KClO4 reacts with a wide variety of fuels. A common example is glucose, C₆H₁₂O₆.
3 KClO₄ + C₆H₁₂O₆ ? 6 H₂O + 6 CO₂ + 3 KCl
When mixed with cane sugar, it can be used as a low explosive, if the necessary confinement is provided. Otherwise the mixture will simply deflagrate with an intense purple flame indicative of potassium salts. Flash compositions used in firecrackers usually consist of fine aluminium powder mixed with potassium perchlorate.

Potassium perchlorate can be used safely in the presence of sulfur; however, potassium chlorate cannot. The common explanation for this is that the sulfur will, given time, produce minute quantities of sulfurous acid and sulfuric acid. These will, in turn, react with potassium chlorate to produce chloric acid, which is highly unstable and can lead to premature ignition of the composition. The corresponding acid of potassium perchlorate, perchloric acid, is stable enough as to prevent spontaneous ignition

Sodium perchlorate is a perchlorate of sodium and has the formula NaClO₄. Sodium perchlorate melts with decomposition at 480 °C.^[1] Its heat of formation is -382.75 kJ mol-1.^[2] It is a white crystalline solid. It is hygroscopic. It is soluble in water and in alcohol. It usually comes as the monohydrate, which has a rhombic crystal structure