Phosphine

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phosphine

[′fä‚sfēn]
(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.

Phosphine

 

(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.

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It was reported by Price and Mills (1988); Mills and Pacheco (1996) that exposure time come to be most effective factor rather than phosphine concentrations for proper management of target pests.
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So, it is suggested that as DNA and RNA contents were reduced and their reduction was enhanced as duration of exposure period increased thus phosphine may acts as insect growth regulators by inflicting its toxicity by targeting molting hormone and juvenile hormone.
Time, concentration and temperature relationships for phosphine toxicity in tests on diapausing larvae of Ephestia elutella (Hubner) (Lepidoptera: Pyralidae).
Phosphine resistance in stored-product insects collected from various grain storage facilities in Morocco.
A review of the mechanisms involved in the action of phosphine as an insecticide and phosphine resistance in stored product insects.
Effects of time and concentration on mortality of phosphine-resistant Sitophilus oryzae (L) fumigated with phosphine.
Resistance to phosphine in stored product insects and a strategy to prevent its increase.
Differences in phosphine uptake between susceptible and resistant strains of insects.
The toxicity of phosphine to the immature stages of resistant and susceptible strains of some common stored product beetles, and implications for their control.
Optimising indoor phosphine fumigation of paddy rice bag-stacks under sheeting for control of resistant insects.