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IUPAC name
Other names
Phosphorus trihydride
Phosphorated hydrogen
Jmol-3D images Image
Molar mass 33.99758 g/mol
Appearance Colorless gas
Odor Garlic-like
Decayed fish-like
Density 1.379 g/l, gas (25 °C)
Melting point −132.8 °C (−207.0 °F; 140.3 K)
Boiling point −87.7 °C (−125.9 °F; 185.5 K)
31.2 mg/100 ml (at 17 °C)
Solubility soluble in alcohol, carbon disulfide, diethyl ether
slightly soluble in benzene, chloroform, ethanol
Vapor pressure 41.3 atm (at 20°C)
210 J·mol−1·K−1
5 kJ·mol−1
Safety data sheet Praxair
Lethal dose or concentration (LD, LC):
3.03 mg/kg (rat, oral)
11 ppm (rat, 4 hr)
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Phosphine or phosphane is a chemical compound of phosphorus. It is the phosphorus analogue of ammonia, with the chemical formula PH3, although the chemical properties of the two compounds are very different.



Phosphine may ignite in open air, although its pyrophoricity is influenced by other impurities, such as diphosphane.


Phosphine is a colorless gas, heavier than air and with a strong unpleasant smell, described as being garlic-like, decayed fish-like or sometimes even that of burned rock, the smell being influenced by the various contaminants, depending on the source of phosphine. Unlike ammonia, phosphine is almost insoluble in water, but more soluble in various organic solvents, like ether or alcohols.


Phosphine is not available to the general public due to its very high toxicity. However, phosphides of certain metals are sometimes sold as pest control agents, and their reaction with water releases phosphine.


The reaction of aluminium phosphide or any other phosphide with water releases phosphine gas.

AlP + 3 H2O → PH3 + Al(OH)3

This reaction is used to kill most vermin in grain silos. Calcium, magnesium, tin, or zinc phosphide can also be hydrolyzed to produce phosphine, although these will also produce diphosphane as a consequence of the P-P bonds present in these metal phosphides.[1]

The most convenient way of obtaining phosphine is through the reaction of elemental phosphorus with a strong basic solution, such as sodium or potassium hydroxide:

4 P + 6 KOH + 3 H2O → PH3 + 3 KH2PO2

Reduction of phosphorus trichloride with lithium aluminium hydride in anhydrous diethyl ether yields phosphine.[2]

Reduction of phosphorus pentoxide with hydrogen in the presence of a nickel catalyst results in phosphine.[3]

Thermal decomposition of hypophosphorous acid (H3PO2) also yields phosphine.[4]

Heating piperidine with red phosphorus in hydrogen will release phosphine.[5]

Phosphine tends to be an unwanted product in various reactions involving phosphorus or phosphorus compounds. The most common way phosphine is encountered is in the reaction of impure calcium carbide with water. In industry, calcium carbide is made by roasting calcium oxide, obtained from rocks, such as calcium carbonate or calcium sulfate. This form of calcium tends to be contaminated with calcium phosphate, which is reduced at high temperatures to calcium phosphide, which in the presence of water hydrolyzes to yield phosphine.

It's recommended you avoid experimenting with phosphine, as, apart from its high toxicity, the phosphine smell is associated with meth labs, and its presence may draw the unwanted attention of the authorities.


Do something else! Phosphine's main use is to kill vermin from grain silos, and it doesn't have other uses.



Phosphine is extremely toxic and may cause death if inhaled even in low doses.


Do not store phosphine! Ever!


Phosphine will eventually oxidize in open air to phosphorus pentoxide and phosphoric acid. Hydrogen peroxide is also good for neutralizing it. Bleach is recommended: "Sodium hypochlorite in aqueous solutions reacts practically instantaneously with phosphine so that such solutions are particularly suitable for removing traces of phosphine from a gas stream." [6].


  1. Fluck, E. (1971). The Chemistry of Phosphine.
  2. Wiberg, E.; Mueller-Schiedmayer, G.; Ber. Dtsch. Chem. Ges.; vol. 92; (1959); p. 2372 - 2384
  3. Neogi, P.; Adhicary, B. B.; Zeitschrift fuer Anorganische und Allgemeine Chemie; vol. 69; (1911); p. 209 - 214
  4. Dulong, P. L.; Ann. Chim. Phys.; vol. 2; (1816); p. 141 - 150
  5. Schenck, R.; Ber.; vol. 36; (1903); p. 979 - 995
  6. Fluck, E. (1971). The Chemistry of Phosphine.

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