Phosphide

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phosphide

[′fä‚sfīd]
(inorganic chemistry)
Binary compound of trivalent phosphorus, as in Na3P.

Phosphide

 

any of the compounds of phosphorus with metals or with nonmetals, such as B, Si, and As, that are more electropositive than phosphorus. Phosphides of nontransition metals and of metals of the copper subgroup, which have the compositions Me3P and Me2P5 in the case of alkali metals, Me3P2 with alkaline-earth metals, and Me3P and MeP2 with metals of the copper subgroup (Me denoting the metal), are ionic, saltlike compounds. Phosphides of alkali and alkaline-earth metals are readily decomposed by water and dilute acids, phosphine being liberated in the process. Phosphides of alkaline-earth metals and metals of the copper subgroup are not stable at elevated temperatures; at relatively high phosphorus concentrations, these phosphides are semiconducting.

Phosphides of transition metals (CrP, MoP, TiP), including lanthanides and actinides (LaP, PuP, U3P4), are chemically stable and do not decompose in water or dilute acids; their physical properties are close to those of either semiconductors (UP, NbP, MnP) or metals (TiP, ZrP). The phosphides of boron, aluminum, and indium are covalent compounds that are high-melting and semiconducting. Phosphides also include volatile molecular compounds, such as those with sulfur, selenium, and tellurium.

Phosphides are formed by a synthesis of the elements at temperatures of 600°–1200°C in a vacuum or atmosphere of inert gases; by the reaction of phosphine with metals and nonmetals or with the corresponding oxides; by the double exchange of phosphine with halides or sulfides, for example, B2S3 + 2PH3 = 2BP + 3H2S; and by the reduction of metal phosphates by hydrogen at high temperatures.

A number of phosphides (InP, GaP) have great importance as semiconductor materials. Zinc phosphide is used as a rodenticide. Phosphides are used in certain nonferrous alloys, such as phosphor bronze, for deoxidation and improvement of antifriction properties. The tendency of certain phosphides to decompose with the liberation of phosphines, which ignite spontaneously in air, is used in the production of signal devices.

L. V. KUBASOVA

References in periodicals archive ?
Weber, Binary and Ternary Transition-Metal Phosphides as HDN Catalysts, J.
Lundstrom, X-Ray Studies of Molybdenum and Tungsten Phosphides, Acta Chem.
Summary: A new molybdenum phosphide (MoP) catalyst was successfully synthesized for CO 2 reforming of CH 4 reaction.
Orally taken zinc phosphide reacts with water and acid in the stomach and produces phosphine gas, which accounts for a large part of the observed toxicity.
Zinc phosphide is a potent gastric irritant; profuse vomiting and abdominal pain are often the first symptoms.
There are significant numbers of studies detailing the effects, treatment, and prognosis of poisoning with aluminum phosphide and other rodenticides, but zinc phosphide has not been that elaborately studied.
Although much ado has been made about the illegal sale of aluminum phosphide, other pesticides on the market may also be harmful - as well as perfectly legal.
Although diazinon is not as dangerous as aluminum phosphide, the United States banned its use in homes and home-gardens a few years ago because the fumes can be dangerous.
But it held three tubes of the semi-conductor indium phosphide with a hazard data sheet warning it could cause skin irritation and blistering.
Since the intercellular carbides and phosphides were the last to freeze, the fact that they remained liquid longer than the rest of the casting also is significant.
The commonest poison ingested was organophosphorus compounds followed by benzodiazepines and aluminium phosphide poisoning.
Key Words: Poisoning, Toxidromes, Organophosphorus compounds, Benzodiazepines, Aluminium phosphide, Suicide