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| Names | |
|---|---|
| Other names Aluminum phosphide Aluminium(III) phosphide Aluminium monophosphide Phostoxin Fumitoxin | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.040.065 |
| EC Number |
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| RTECS number |
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| UNII | |
| UN number | 1397 3048 |
| |
| |
| Properties | |
| AlP | |
| Molar mass | 57.9552 g/mol |
| Appearance | Yellow or gray crystals |
| Odor | garlic-like |
| Density | 2.85 g/cm3 |
| Melting point | 2,530 °C (4,590 °F; 2,800 K) |
| reacts | |
| Band gap | 2.5 eV (indirect)[1] |
Refractive index (nD) | 2.75 (IR), ~3 (Vis)[1] |
| Structure | |
| Zincblende | |
| T2d-F43m | |
a = 546.35 pm | |
| Tetrahedral | |
| Thermochemistry | |
Std molar entropy(S⦵298) | 47.3 J/mol K |
Std enthalpy of formation(ΔfH⦵298) | −164.4 kJ/mol |
| Hazards | |
| GHS labelling: | |
   | |
| Danger | |
| H260,H300,H311,H330,H400 | |
| P223,P231+P232,P260,P264,P270,P271,P273,P280,P284,P301+P310,P302+P352,P304+P340,P310,P312,P320,P321,P322,P330,P335+P334,P361,P363,P370+P378,P391,P402+P404,P403+P233,P405,P501 | |
| NFPA 704 (fire diamond) | |
| Flash point | > 800 °C (1,470 °F; 1,070 K) |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 11.5 mg/kg |
| Safety data sheet (SDS) | External MSDS |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Aluminium phosphide is a highly toxicinorganic compound with the chemical formula AlP, used as a wideband gap semiconductor and afumigant. This colorless solid is generally sold as a grey-green-yellow powder or pellet due to the presence of impurities arising fromhydrolysis andoxidation.
It is used by farmers, pest controllers, gamekeepers and estate managers as a fumigant pesticide.
AlP crystals are dark grey to dark yellow in color and have azincblende crystal structure[2] with a lattice constant of 5.4510 Å at 300 K.[3] They are thermodynamically stable up to 1,000 °C (1,830 °F).[4]
Aluminium phosphide reacts vigorously withwater or acids to releasephosphine.[5] The phosphine is the basis of thetoxicity of AlP.
AlP is synthesized bycombination of the elements:[4][6]
AlP is used as arodenticide,insecticide, andfumigant for stored cereal grains. It is used to kill small verminousmammals such asmoles androdents. The tablets or pellets, known as "wheat pills", typically also contain other chemicals that evolveammonia andcarbon dioxide (e.g.ammonium carbamate), which help to reduce the potential for spontaneousignition orexplosion of the phosphine gas.[7]
AlP is used as both a fumigant and an oral pesticide. As a rodenticide, aluminium phosphide pellets are provided as a mixture with food for consumption by the rodents. The acid in the digestive system of the rodent reacts with the phosphide to generate the toxic phosphine gas. Other pesticides similar to aluminium phosphide arezinc phosphide andcalcium phosphide. In this application, aluminium phosphide can be encountered under various brand names, e.g.PestPhos,Quickphos,Celphos,Fostox,Fumitoxin,Phostek,Phostoxin,Talunex,Fieldphos,PH3, andWeevil-Cide. It generates phosphine gas according to the following hydrolysis equation:[6]
AlP + 3 H2O → Al(OH)3 + PH3
It is used as a fumigant when other pesticide applications are impractical and when structures and installations are being treated, such as in ships, aircraft, and grain silos. All of these structures can be effectively sealed or enclosed in a gastight membrane, thereby containing and concentrating the phosphine fumes. Fumigants are also applied directly to rodent burrows.[8]
Industrially, AlP is asemiconductor material that is usuallyalloyed with other binary materials for applications in devices such aslight-emitting diodes (e.g.aluminium gallium indium phosphide).[9]
Highly poisonous, aluminium phosphide has been used for suicide.[10] Fumigation has also caused unintentional deaths.[11][12][13][14] Known as "rice tablet" in Iran, for its use to preserve rice, there have been frequent incidents of accidental or intentional death. There is a campaign by the Iranian Forensic Medicine Organization to stop its use as a pesticide.[15][16]
Recycling of used aluminium phosphide containers caused the death of three family members inAlcalá de Guadaira, Spain. They had been keeping them in plastic sacks in their bathroom. The deaths occurred accidentally due to aluminium phosphide reacting with water or moisture, and becomingphosphine, leading to their death within hours.[17]
Aluminium phosphide poisoning is considered a wide-scale problem in the Indian subcontinent.[18][19]
It is manufactured byUPL Corporation globally,Intech Organics in India, Scimplify in the USA and others.
In the UK, a license and "appropriate training" are required to purchase it.[20]As of 2010, it was still available over the counter in India though "stricter norms" according to one author had been adopted.[21]
In the EU, it is an approved pesticide. The expiration of the approval was postponed twice, the last time on November 13, 2025.[22]
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