Phosphine (

IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...

name: phosphane) is a colorless, flammable, highly toxic compound with the

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

, classed as a

pnictogen hydride Pnictogen hydrides or hydrogen pnictides are binary compounds of hydrogen with pnictogen ( or ; from "to choke" and -gen, "generator") atoms (elements of group 15: nitrogen, phosphorus, arsenic, antimony, bismuth, and moscovium) covalently bonded ...

. Pure phosphine is odorless, but technical grade samples have a highly

unpleasant odor An odor (American English) or odour (English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is a smell or a scent caused by one or more volatilized ...

like rotting fish, due to the presence of

substituted Substitution may refer to: Arts and media *Substitution (poetry), a variation in poetic scansion *Substitution (theatre), an acting methodology Music *Chord substitution, swapping one chord for a related one within a chord progression *Tritone ...

phosphine and

diphosphane Diphosphane, or diphosphine, is an inorganic compound with the chemical formula . This colourless liquid is one of several binary phosphorus hydrides. It is the impurity that typically causes samples of phosphine to ignite in air. Properties, ...

(). With traces of present, is spontaneously flammable in air (

pyrophoric A substance is pyrophoric (from , , 'fire-bearing') if it ignites spontaneously in air at or below (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). Examples are organolithium compounds and triethylb ...

), burning with a luminous flame. Phosphine is a highly toxic respiratory poison, and is

immediately dangerous to life or health The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent adver ...

at 50 ppm. Phosphine has a

trigonal pyramidal In chemistry, a trigonal pyramid is a molecular geometry with one atom at the apex and three atoms at the corners of a trigonal base, resembling a tetrahedron (not to be confused with the tetrahedral geometry). When all three atoms at the corner ...

structure. Phosphines are compounds that include and the

organophosphine Organophosphines are organophosphorus compounds with the formula PR''n''H3−''n'', where R is an organic substituent. These compounds can be classified according to the value of ''n'': primary phosphines (''n'' = 1), secondary phosphin ...

s, which are derived from by substituting one or more hydrogen atoms with organic groups. They have the general formula . Phosphanes are saturated phosphorus hydrides of the form , such as

triphosphane Triphosphane (IUPAC systematic name) or triphosphine is an inorganic compound having the chemical formula . It can be generated from diphosphine but is highly unstable at room temperature: : Samples have been isolated by gas chromatography ...

. Phosphine () is the smallest of the phosphines and the smallest of the phosphanes.

History

Philippe Gengembre (1764–1838), a student of

Lavoisier Antoine-Laurent de Lavoisier ( ; ; 26 August 17438 May 1794),
CNRS (

white phosphorus White phosphorus, yellow phosphorus, or simply tetraphosphorus (P4) is an allotrope of phosphorus. It is a translucent waxy solid that quickly yellows in light (due to its photochemical conversion into red phosphorus), and impure white phospho ...

in an aqueous solution of

potash Potash ( ) includes various mined and manufactured salts that contain potassium in water- soluble form.

(potassium carbonate).For further information about the early history of phosphine, see: * ''The Encyclopædia Britannica'' (1911 edition), vol. 21, p. 480:
Phosphorus: Phosphine.
* Thomas Thomson, ''A System of Chemistry'', 6th ed. (London, England: Baldwin, Cradock, and Joy, 1820), vol. 1
p. 272.
Perhaps because of its strong association with elemental

phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...

, phosphine was once regarded as a gaseous form of the element, but Lavoisier (1789) recognised it as a combination of phosphorus with hydrogen and described it as ''phosphure d'hydrogène'' (phosphide of hydrogen).Note: *
On p. 222
of his ''Traité élémentaire de chimie'', vol. 1, (Paris, France: Cuchet, 1789), Lavoisier calls the compound of phosphorus and hydrogen ''"phosphure d'hydrogène"'' (hydrogen phosphide). However
on p. 216
, he calls the compound of hydrogen and phosphorus ''"Combinaison inconnue."'' (unknown combination), yet in a footnote, he says about the reactions of hydrogen with sulfur and with phosphorus: ''"Ces combinaisons ont lieu dans l'état de gaz & il en résulte du gaz hydrogène sulfurisé & phosphorisé."'' (These combinations occur in the gaseous state, and there results from them sulfurized and phosphorized hydrogen gas.) * In Robert Kerr's 1790 English translation of Lavoisier's ''Traité élémentaire de chimie'' ... — namely, Lavoisier with Robert Kerr, trans., ''Elements of Chemistry'' ... (Edinburgh, Scotland: William Creech, 1790) — Kerr translates Lavoisier's ''"phosphure d'hydrogène"'' as "phosphuret of hydrogen"
p. 204
, and whereas Lavoisier — on p. 216 of his ''Traité élémentaire de chimie'' ... — gave no name to the combination of hydrogen and phosphorus, Kerr calls it "hydruret of phosphorus, or phosphuret of hydrogen"
p. 198
. Lavoisier's note about this compound — ''"Combinaison inconnue."'' — is translated: "Hitherto unknown." Lavoisier's footnote is translated as: "These combinations take place in the state of gas, and form, respectively, sulphurated and phosphorated oxygen gas." The word "oxygen" in the translation is an error because the original text clearly reads ''"hydrogène"'' (hydrogen). (The error was corrected in subsequent editions.) In 1844, Paul Thénard, son of the French chemist

Louis Jacques Thénard Louis Jacques Thénard (4 May 177721 June 1857) was a French chemist. Life He was born in a farm cottage near Nogent-sur-Seine in the Champagne district the son of a farm worker. In the post-Revolution French educational system, most boys rec ...

, used a

cold trap In vacuum applications, a cold trap is a device that condenses all vapors except the permanent gases (hydrogen, oxygen, and nitrogen) into a liquid or solid. The most common objective is to prevent vapors being evacuated from an experiment from ...

to separate diphosphine from phosphine that had been generated from

calcium phosphide Calcium phosphide (CP) is the inorganic compound with the formula Ca3P2. It is one of several phosphides of calcium, being described as the salt-like material composed of Ca2+ and P3−. Other, more exotic calcium phosphides have the formula CaP ...

, thereby demonstrating that is responsible for spontaneous flammability associated with , and also for the characteristic orange/brown color that can form on surfaces, which is a polymerisation product. He considered diphosphine's formula to be , and thus an intermediate between elemental phosphorus, the higher polymers, and phosphine.

Calcium phosphide Calcium phosphide (CP) is the inorganic compound with the formula Ca3P2. It is one of several phosphides of calcium, being described as the salt-like material composed of Ca2+ and P3−. Other, more exotic calcium phosphides have the formula CaP ...

(nominally ) produces more than other phosphides because of the preponderance of P-P bonds in the starting material. The name "phosphine" was first used for organophosphorus compounds in 1857, being analogous to organic

amine In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...

s ().In 1857,

August Wilhelm von Hofmann August Wilhelm von Hofmann (8 April 18185 May 1892) was a German chemist who made considerable contributions to organic chemistry. His research on aniline helped lay the basis of the aniline-dye industry, and his research on coal tar laid the g ...

announced the synthesis of organic compounds containing phosphorus, which he named "

trimethylphosphine Trimethylphosphine is an organophosphorus compound with the formula P(CH3)3, commonly abbreviated as PMe3. This colorless liquid has a strongly unpleasant odor, characteristic of alkylphosphines. The compound is a common ligand in coordination c ...

" and "

triethylphosphine Triethylphosphine is the organophosphorus compound with the formula P(CH2CH3)3, commonly abbreviated as PEt3. It is a colorless liquid with an unpleasant odor characteristic of alkylphosphines. The compound is a common ligand in organometallic c ...

", in analogy with "amine" (organo-nitrogen compounds), "arsine" (organo-arsenic compounds), and "stibine" (organo-antimony compounds). The gas was named "phosphine" by 1865 (or earlier).

Structure and reactions

is a

trigonal pyramid In chemistry, a trigonal pyramid is a molecular geometry with one atom at the apex and three atoms at the corners of a trigonal base, resembling a tetrahedron (not to be confused with the tetrahedral geometry). When all three atoms at the corner ...

al molecule with ''C''_3''v''

molecular symmetry In chemistry, molecular symmetry describes the symmetry present in molecules and the classification of these molecules according to their symmetry. Molecular symmetry is a fundamental concept in chemistry, as it can be used to predict or explai ...

. The

length Length is a measure of distance. In the International System of Quantities, length is a quantity with Dimension (physical quantity), dimension distance. In most systems of measurement a Base unit (measurement), base unit for length is chosen, ...

of the P−H bond is 1.42 Å, the H−P−H

bond angle Molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. It includes the general shape of the molecule as well as bond lengths, bond angles, torsional angles and any other geometrical parameters that deter ...

s are 93.5 °. The dipole moment is 0.58 D, which increases with

substitution Substitution may refer to: Arts and media *Substitution (poetry), a variation in poetic scansion * Substitution (theatre), an acting methodology Music *Chord substitution, swapping one chord for a related one within a chord progression *Tritone ...

methyl group In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula (whereas normal methane has the formula ). In formulas, the group is often abbreviated a ...

s in the series: , 1.10 D; , 1.23 D; , 1.19 D. In contrast, the dipole moments of amines decrease with substitution, starting with

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

, which has a dipole moment of 1.47 D. The low dipole moment and almost orthogonal bond angles lead to the conclusion that in the P−H bonds are almost entirely and phosphorus 3s orbital contributes little to the P-H bonding. For this reason, the lone pair on phosphorus is predominantly formed by the 3s orbital of phosphorus. The upfield chemical shift of its ³¹P NMR signal accords with the conclusion that the lone pair electrons occupy the 3s orbital (Fluck, 1973). This electronic structure leads to a lack of

nucleophilicity In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...

in general and lack of basicity in particular (p''K''_aH = −14), as well as an ability to form only weak

hydrogen bonds In chemistry, a hydrogen bond (H-bond) is a specific type of molecular interaction that exhibits partial covalent character and cannot be described as a purely electrostatic force. It occurs when a hydrogen (H) atom, covalently bonded to a mo ...

. The aqueous

solubility In chemistry, solubility is the ability of a chemical substance, substance, the solute, to form a solution (chemistry), solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form su ...

of is slight: 0.22 cm³ of gas dissolves in 1 cm³ of water. Phosphine dissolves more readily in non-polar solvents than in water because of the non-polar P−H bonds. It is technically

amphoteric In chemistry, an amphoteric compound () is a molecule or ion that can react both as an acid and as a base. What exactly this can mean depends on which definitions of acids and bases are being used. Etymology and terminology Amphoteric is d ...

in water, but acid and base activity is poor. Proton exchange proceeds via a

phosphonium In chemistry, the term phosphonium (more obscurely: phosphinium) describes polyatomic cations with the chemical formula (where R is a hydrogen or an alkyl, aryl, organyl or halogen group). These cations have tetrahedral structures. The ...

() ion in acidic solutions and via

phosphanide Phosphanides are chemicals containing the H2sup>− anion. This is also known as the phosphino anion or phosphido ligand. The IUPAC name can also be dihydridophosphate(1−). It can occur as a group phosphanyl -PH2 in organic compounds or ligand ...

() at high pH, with equilibrium constants ''K''_b = and ''K''_a = . Phosphine reacts with water only at high pressure and temperature, producing

phosphoric acid Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, ...

and hydrogen: Burning phosphine in the air produces

Preparation and occurrence

Phosphine may be prepared in a variety of ways. Industrially it can be made by the reaction of white

with

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

, producing

potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...

sodium hypophosphite Sodium hypophosphite (NaPO2H2, also known as sodium phosphinate) is the sodium salt of hypophosphorous acid and is often encountered as the monohydrate, NaPO2H2·H2O. It is a solid at room temperature, appearing as odorless white crystals. It is s ...

as a by-product. Alternatively, the acid-catalyzed

disproportionation In chemistry, disproportionation, sometimes called dismutation, is a redox reaction in which one compound of intermediate oxidation state converts to two compounds, one of higher and one of lower oxidation state. The reverse of disproportionatio ...

of white

yields

and phosphine. Both routes have industrial significance; the acid route is the preferred method if further reaction of the phosphine to substituted phosphines is needed. The acid route requires purification and pressurizing.

Laboratory routes

It is prepared in the laboratory by

phosphorous acid Phosphorous acid (or phosphonic acid) is the Compound (chemistry), compound described by the chemical formula, formula . It is diprotic (readily ionizes two protons), not triprotic as might be suggested by its formula. Phosphorous acid is an in ...

: Alternative methods are the hydrolysis

zinc phosphide Zinc phosphide ( Zn3 P2) is an inorganic chemical compound. It is a grey solid, although commercial samples are often dark or even black. It is used as a rodenticide. Zn3P2 is a II-V semiconductor with a direct band gap of 1.5 eV and may have ap ...

: Some other metal phosphides could be used including

aluminium phosphide Aluminium phosphide is a highly toxic inorganic compound with the chemical formula AlP, used as a wide band gap semiconductor and a fumigant. This colorless solid is generally sold as a grey-green-yellow powder due to the presence of impurities ...

, or

. Pure samples of phosphine, free from , may be prepared using the action of

phosphonium iodide Phosphonium iodide is a chemical compound with the formula . It is an example of a salt containing an unsubstituted phosphonium cation (). Phosphonium iodide is commonly used as storage for phosphine and as a reagent for substituting phosphorus int ...

Occurrence

Phosphine is a worldwide constituent of the Earth's atmosphere at very low and highly variable concentrations. It may contribute significantly to the global phosphorus biochemical cycle. The most likely source is reduction of

phosphate Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...

in decaying organic matter, possibly via partial reductions and

s, since environmental systems do not have known reducing agents of sufficient strength to directly convert phosphate to phosphine. It is also found in

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

's atmosphere.

Possible extraterrestrial biosignature

In 2020 a spectroscopic analysis was reported to show signs of phosphine in the

atmosphere of Venus The atmosphere of Venus is the very dense layer of gases surrounding the planet Venus. Venus's atmosphere is composed of 96.5% carbon dioxide and 3.5% nitrogen, with other chemical compounds present only in trace amounts. It is much denser and ho ...

in quantities that could not be explained by known abiotic processes. Later re-analysis of this work showed interpolation errors had been made, and re-analysis of data with the fixed algorithm do not result in the detection of phosphine. The authors of the original study then claimed to detect it with a much lower concentration of 1 ppb.

Applications

Organophosphorus chemistry

Phosphine is a precursor to many

organophosphorus compounds Organophosphorus chemistry is the scientific study of the synthesis and properties of organophosphorus compounds, which are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbo ...

. It reacts with formaldehyde in the presence of

hydrogen chloride The Chemical compound, compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hyd ...

to give

tetrakis(hydroxymethyl)phosphonium chloride Tetrakis(hydroxymethyl)phosphonium chloride (THPC) is an organophosphorus compound with the chemical formula (CH2OH)4l. It is a white water-soluble salt with applications as a precursor to fire-retardant materials and as a microbiocide in commerc ...

, which is used in textiles. The

hydrophosphination Hydrophosphination is the insertion of a double bond into a phosphorus-hydrogen bond. Often the hydrophosphination makes phosphorus-carbon bonds by addition of P-H bonds to carbon-carbon multiple bonds, but the reaction is probably most useful in ...

of alkenes is versatile route to a variety of phosphines. For example, in the presence of basic catalysts adds of

Michael acceptor In organic chemistry, the Michael reaction or Michael 1,4 addition is a reaction between a Michael donor (an enolate or other nucleophile) and a Michael acceptor (usually an α,β-unsaturated carbonyl) to produce a Michael adduct by creating a c ...

s. Thus with

acrylonitrile Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group () linked to a nitrile (). It is an im ...

, it reacts to give

tris(cyanoethyl)phosphine Tris(cyanoethyl)phosphine is the organophosphorus compound with the formula P(CH2CH2CN)3. It is white solid that is air stable, which is unusual for a trialkylphosphine. It is prepared by the hydrophosphination of acrylonitrile with phosphine. T ...

: Acid catalysis is applicable to hydrophosphination with

isobutylene Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula . It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value. Product ...

and related analogues: where R is , alkyl, etc.

Microelectronics

Phosphine is used as a

dopant A dopant (also called a doping agent) is a small amount of a substance added to a material to alter its physical properties, such as electrical or optics, optical properties. The amount of dopant is typically very low compared to the material b ...

in the

semiconductor A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping level ...

industry, and a precursor for the deposition of

compound semiconductor Semiconductor materials are nominally small band gap insulators. The defining property of a semiconductor material is that it can be compromised by doping it with impurities that alter its electronic properties in a controllable way. Because of ...

s. Commercially significant products include

gallium phosphide Gallium phosphide (GaP), a phosphide of gallium, is a compound semiconductor material with an indirect band gap of 2.24 eV at room temperature. Impure polycrystalline material has the appearance of pale orange or grayish pieces. Undoped single cr ...

and

indium phosphide Indium phosphide (InP) is a binary semiconductor composed of indium and phosphorus. It has a face-centered cubic ("zincblende (crystal structure), zincblende") crystal structure, identical to that of gallium arsenide, GaAs and most of the List of ...

Fumigant (pest control)

Phosphine is an attractive fumigant because it is lethal to insects and rodents, but degrades to phosphoric acid, which is non-toxic. As sources of phosphine, for farm use, pellets of

(AlP),

(), or

() are used. These phosphides release phosphine upon contact with atmospheric water or rodents' stomach acid. These pellets also contain reagents to reduce the potential for

ignition Ignition may refer to: Science and technology * Firelighting, the human act of creating a fire for warmth, cooking and other uses * Combustion, an exothermic chemical reaction between a fuel and an oxidant * Fusion ignition, the point at which a ...

explosion An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated ...

of the released phosphine. An alternative is the use of phosphine gas itself which requires dilution with either or or even air to bring it below the flammability point. Use of the gas avoids the issues related with the solid residues left by metal phosphide and results in faster, more efficient control of the target pests. One problem with phosphine fumigants is the increased resistance by insects.

Toxicity and safety

Deaths have resulted from accidental exposure to fumigation materials containing

or phosphine. It can be absorbed either by

inhalation Inhalation (or inspiration) happens when air or other gases enter the lungs. Inhalation of air Inhalation of air, as part of the cycle of breathing, is a vital process for all human life. The process is autonomic (though there are exceptions ...

transdermal Transdermal is a route of administration wherein active ingredients are delivered across the skin for systemic distribution. Examples include transdermal patches used for medicine delivery. The drug is administered in the form of a patch or ointm ...

ly. As a respiratory poison, it affects the transport of oxygen or interferes with the utilization of oxygen by various cells in the body. Exposure results in

pulmonary edema Pulmonary edema (British English: oedema), also known as pulmonary congestion, is excessive fluid accumulation in the tissue or air spaces (usually alveoli) of the lungs. This leads to impaired gas exchange, most often leading to shortness ...

(the lungs fill with fluid). Phosphine gas is heavier than air so it stays near the floor. Phosphine appears to be mainly a redox toxin, causing cell damage by inducing

oxidative stress Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. Disturbances in the normal ...

and mitochondrial dysfunction. Resistance in insects is caused by a mutation in a mitochondrial metabolic gene. Phosphine can be absorbed into the body by inhalation. The main target organ of phosphine gas is the respiratory tract. According to the 2009 U.S.

National Institute for Occupational Safety and Health The National Institute for Occupational Safety and Health (NIOSH, ) is the List of United States federal agencies, United States federal agency responsible for conducting research and making recommendations for the prevention of work-related occ ...

(NIOSH) pocket guide, and U.S.

Occupational Safety and Health Administration The Occupational Safety and Health Administration (OSHA; ) is a regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. The United States Congress established ...

(OSHA) regulation, the 8 hour average respiratory exposure should not exceed 0.3 ppm. NIOSH recommends that the short term respiratory exposure to phosphine gas should not exceed 1 ppm. The

Immediately Dangerous to Life or Health The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent adver ...

level is 50 ppm. Overexposure to phosphine gas causes nausea, vomiting, abdominal pain, diarrhea, thirst, chest tightness,

dyspnea Shortness of breath (SOB), known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that ...

(breathing difficulty), muscle pain, chills, stupor or syncope, and pulmonary edema. Phosphine has been reported to have the odor of decaying fish or garlic at concentrations below 0.3 ppm. The smell is normally restricted to laboratory areas or phosphine processing since the smell comes from the way the phosphine is extracted from the environment. However, it may occur elsewhere, such as in industrial waste landfills. Exposure to higher concentrations may cause

olfactory fatigue Olfactory fatigue, also known as odor fatigue, odor habituation, olfactory adaptation, or noseblindness, is the temporary, normal inability to distinguish a particular odor after a prolonged exposure to that airborne compound. For example, when en ...

Fumigation hazards

Phosphine is used for

pest control Pest control is the regulation or management of a species defined as a pest (organism), pest; such as any animal, plant or fungus that impacts adversely on human activities or environment. The human response depends on the importance of the da ...

, but its usage is strictly regulated due to high toxicity. Gas from phosphine has high mortality rate and has caused deaths in Sweden and other countries. Because the previously popular

fumigant Fumigation is a method of pest control or the removal of harmful microorganisms by completely filling an area with gaseous pesticides, or fumigants, to suffocate or poison the pests within. It is used to control pests in buildings (structural ...

methyl bromide Bromomethane, commonly known as methyl bromide, is an organobromine compound with chemical formula, formula Carbon, CHydrogen, H3Bromine, Br. This colorless, odorless, nonflammable gas is Bromine cycle, produced both industrially and biologically ...

has been phased out in some countries under the

Montreal Protocol The Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. It was agreed on 16 ...

, phosphine is the only widely used, cost-effective, rapidly acting fumigant that does not leave residues on the stored product. Pests with high levels of resistance toward phosphine have become common in Asia, Australia and Brazil. High level resistance is also likely to occur in other regions, but has not been as closely monitored. Genetic variants that contribute to high level resistance to phosphine have been identified in the

dihydrolipoamide dehydrogenase Dihydrolipoamide dehydrogenase (DLD), also known as dihydrolipoyl dehydrogenase, mitochondrial, is an enzyme that in humans is encoded by the ''DLD'' gene. DLD is a flavoprotein enzyme that oxidizes dihydrolipoamide to lipoamide. Dihydrolipoami ...

gene. Identification of this gene now allows rapid molecular identification of resistant insects.

Explosiveness

Phosphine gas is denser than air and hence may collect in low-lying areas. It can form explosive mixtures with air, and may also self-ignite.

In fiction

Anne McCaffrey Anne Inez McCaffrey (1 April 1926 – 21 November 2011) was an American writer known for the ''Dragonriders of Pern'' science fiction series. She was the first woman to win a Hugo Award for fiction (Best Novella, ''Weyr Search'', 1968) an ...

's Dragonriders of Pern series features genetically engineered dragons that breathe fire by producing phosphine by extracting it from minerals of their native planet. In the 2008

pilot An aircraft pilot or aviator is a person who controls the flight of an aircraft by operating its Aircraft flight control system, directional flight controls. Some other aircrew, aircrew members, such as navigators or flight engineers, are al ...

of the crime drama television series ''

Breaking Bad ''Breaking Bad'' is an American crime drama television series created and produced by Vince Gilligan for AMC (TV channel), AMC. Set and filmed in Albuquerque, New Mexico, the series follows Walter White (Breaking Bad), Walter White (Bryan Cran ...

'', Walter White poisons two rival gangsters by adding red phosphorus to boiling water to produce phosphine gas. However, this reaction in reality would require white phosphorus instead, and for the water to contain

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

Notes

References

External links

International Chemical Safety Card 0694
!-- Syntax: -->
CDC – Phosphine – NIOSH Workplace Safety and Health Topic
{{Authority control Fumigants Functional groups Industrial gases * Phosphorus hydrides Phosphorus(−III) compounds Blood agents Pyrophoric materials