Ammonium perchlorate | |
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Ammonium perchlorate |
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Other names
AP |
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Identifiers | |
CAS number | 7790-98-9 |
ChemSpider | 23041 |
EC number | 232-235-1 |
UN number | 1442 |
RTECS number | SC7520000 |
Jmol-3D images | Image 1 |
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Properties | |
Molecular formula | NH4ClO4 |
Molar mass | 117.49 g/mol |
Appearance | white granular |
Density | 1.95 g/cm3 |
Melting point |
Exothermic decomposition before melting at >200 °C[1] |
Solubility in water | 11.56 g/100 mL (0 °C) 20.85 g/100 mL (20 °C) 57.01 g/100 mL (100 °C) |
Solubility | soluble in methanol partially soluble in acetone insoluble in ether |
Structure | |
Crystal structure | Orthorhombic (< 513 K) Cubic (> 513 K) |
Hazards | |
MSDS | External MSDS |
EU Index | 017-009-00-0 |
EU classification | Oxidant (O) |
R-phrases | R9, R44 |
S-phrases | (S2), S14, S16, S27, S36/37 |
NFPA 704 |
0
1
4
OX
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Related compounds | |
Other anions | Ammonium chlorate Ammonium chloride |
Other cations | Potassium perchlorate Sodium perchlorate Lithium perchlorate |
Related compounds | Perchloric acid |
(verify) (what is: / ?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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Infobox references |
Ammonium perchlorate is an inorganic compound with the formula NH4ClO4. It is the salt of perchloric acid and ammonia. It is a powerful oxidizer, which is why its main use is in solid propellants. It has been implicated in a number of industrial accidents.
Contents |
Ammonium perchlorate (AP) is produced by reaction between ammonia and perchloric acid, and is the driver behind the industrial production of perchloric acid. It also can be prepared by treatment of ammonium salts with sodium perchlorate. This process exploits the fact that the solubility of NH4ClO4 is about 10% of that for sodium perchlorate.[2]
AP crystallises into colorless rhombohedra.
Like most ammonium salts, ammonium perchlorate decomposes before melting. Mild heating results in the evolution of chlorine, nitrogen, oxygen, and water.
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.[3] Strong heating may lead to explosions. Complete reactions leave no residue. Pure crystals cannot sustain a flame below the pressure of 20 bar (2 MPa).
AP is a Class 4 oxidizer (can undergo an explosive reaction) for particle sizes over 15 micrometres[4] and is classified as an explosive for particle sizes less than 15 micrometres.[5][6]
The vast majority of ammonium perchlorate is used to make solid propellants.[7] When AP is mixed with a fuel (like a powdered aluminum and/or with an elastomeric binder), it can generate self-sustained combustion at far under atmospheric pressure. It is an important oxidizer with a decades-long history of use in solid rocket propellants — space launch (including the Space Shuttle Solid Rocket Booster), military, amateur, and hobby high-power rockets, as well as in some fireworks.
Some "breakable" epoxy adhesives contain suspensions of AP. Upon heating to 300 °C, the AP degrades the organic adhesive, breaking the cemented joint.
Perchlorate itself confers little acute toxicity. For example, sodium perchlorate has an LD50 of 2-4 g/kg and is eliminated rapidly after ingestion.[2] However, chronic exposure to perchlorates, even in low concentrations, has been shown to cause various thyroid problems, as it is taken up in place of iodine.