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(inorganic chemistry)
PH3 Poisonous, colorless, spontaneously flammable gas with garlic aroma; soluble in alcohol, slightly soluble in cold water; boils at -85°C; used in organic reactions. Also known as hydrogen phosphide; phosphoretted hydrogen.



(also hydrogen phosphide), PH3, a colorless gas with the odor of rotten fish. Phosphine has a density of 1.55 g/liter, a melting point of –133.8°C, and a boiling point of – 87.8°C at 25°C and a pressure of 0.1 meganewton/m2 (1 kilogram-force/cm2); 1 volume of water dissolves approximately 0.25 volume of PH3. When heated, phosphine decomposes into phosphorus and hydrogen. The chemical properties of phosphine are somewhat similar to those of ammonia; the compound forms phosphonium salts, for example, PH4I. Phosphine is a strong reducing agent. It ignites in air at temperatures above 100°C; in the presence of a small amount of diphosphine vapor, it ignites spontaneously to form a white smoke—phosphorus pentoxide. Mixtures of PH3 and oxygen are explosive (the reaction proceeding by a chain mechanism).

Phosphine (with P2H4 vapors present as an impurity) is produced by the reaction of calcium phosphide (Ca3P2) with water; by heating white phosphorus with a caustic alkali solution (the method used by the French chemist P. Gengembre, who in 1783 was the first to produce phosphine); by thermal decomposition of phosphorous or hypophosphorous acid; and by the reaction of alkalies with phosphonium halides. PH3 is invariably formed during the electrothermal production of white phosphorus from phosphates.

PH3 is exceedingly toxic. In the event of poisoning, the victim must be exposed to fresh air and given artificial respiration.

Also known are self-igniting diphosphine (P2H4; boiling point, 56°C) and a solid form of the compound, the structure of which has not been determined.

References in periodicals archive ?
The 13C NMR chemical shifts of thioamide with Pd(II) tris-4-chlorophenyl phosphine complexes are given in the experimental section.
Such cases of phosphine poising have been reported from India where cheaper household pesticides are used without being aware of its severe toxic effects.
The cause of renal failure can be due to phosphine or due to severe hypotension.
Moreover, because many other tissues have been identified to be susceptible to phosphine gas, a more comprehensive study is required to investigate if this residue is capable of causing damage to organs such as the brain, lung, heart, intestine, etc.
For each individual test, each strain of Tribolium castaneum (30 insects in one beaker) in three repeats, were placed in a jar along with half kilogram infested grains for treatment with different concentrations of phosphine gas (200, 300, 400, 500 ppm) for a recommended exposure period of five days.
The US Environmental Protection Agency has cited studies showing that inhalation of phosphine can result in respiratory, neurological and gastrointestinal effects.
Oxygenation of Phosphine speeds up its action, allowing it to perform its function in five-hour fumigations, rather than 10-day treatments.
It is important to test the fumigation on eggs and pupae because, in general, eggs and pupae are more tolerant of phosphine than larvae and adults," says Liu.
Thus, the objective of this work was to evaluate the insecticide activity of the diatomaceous earth at different temperatures for populations of Tribolium castaneum and Rhyzopertha dominica, respectively, resistant and susceptible to phosphine.
In the latter case it may be contaminated with arsenic and phosphorus compounds that result in the generation of arsine and phosphine when the calcium carbide is treated with water to form acetylene.
Phosphine is a very strong reducing agent that inhibits cellular enzymes involved in several metabolic processes.