View source for Phosphine

{{short description|Chemical compound hydrogen phosphide}}
{{About|{{chem2|PH3}}|organic derivatives| Organophosphine |the visual phenomenon|phosphene|the star|Kepler-289}}
{{for|primary hyperoxaluria phase 3|Primary hyperoxaluria}}
{{Distinguish|phosgene}}
{{Use dmy dates|date=April 2025}}
{{chembox
| verifiedrevid = 464205019
| ImageFile1 = Phosphine.svg
| ImageName1 = Skeletal formula of phosphine
| ImageClass1 = skin-invert
| ImageFileL1 = Phosphine-3D-balls.png
| ImageNameL1 = Ball-and-stick model of phosphine
| ImageFileR1 = Phosphine-underside-3D-vdW.png
| ImageNameR1 = Spacefill model of phosphine
| ImageCaptionR1 = {{legend|orange|Phosphorus, P}}{{legend|white|Hydrogen, H}}
| IUPACName = Phosphane
| OtherNames = Hydrogen phosphide<br/>Phosphamine<br/>Phosphorus trihydride<br/>Phosphorated hydrogen
|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 22814
| InChI = 1/H3P/h1H3
| InChIKey = XYFCBTPGUUZFHI-UHFFFAOYAP
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 30278
| SMILES = P
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/H3P/h1H3
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = XYFCBTPGUUZFHI-UHFFFAOYSA-N
| CASNo = 7803-51-2
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = FW6947296I
| PubChem = 24404
| EINECS = 232-260-8
| UNNumber = 2199
| RTECS = SY7525000
| Gmelin = 287
  }}
|Section2={{Chembox Properties
| Formula = {{chem2|PH3}}
| MolarMass = 33.99758{{nbsp}}g/mol
| Appearance = Colourless gas
| Odor = odorless as pure compound; fish-like or garlic-like commercially<ref name=PGCH/>
| Density = 1.379{{nbsp}}g/L, gas (25{{nbsp}}°C)
| Solubility = 31.2{{nbsp}}mg/100{{thinsp}}ml (17{{nbsp}}°C)
| SolubleOther = Soluble in alcohol, [[diethyl ether|ether]], {{chem2|CS2|link=Carbon disulfide}} <br /> slightly soluble in [[benzene]], [[chloroform]], [[ethanol]]
| MeltingPtC = -132.8
| BoilingPtC = -87.7
| Viscosity = 1.1×10<sup>−5</sup>{{nbsp}}Pa⋅s
| VaporPressure = 41.3{{nbsp}}atm (20{{nbsp}}°C)<ref name=PGCH/>
| RefractIndex = 2.144
| ConjugateAcid = [[Phosphonium#Phosphonium, PH+4|Phosphonium]] ({{Chem2|PH4+}})
  }}
|Section3={{Chembox Structure
| MolShape = Trigonal pyramidal
| Dipole = 0.58{{nbsp}}[[Debye|D]]
  }}
|Section4={{Chembox Thermochemistry
| DeltaHf = 5{{nbsp}}kJ/mol<ref name=b1>{{cite book| last= Zumdahl |first=Steven S.|title =Chemical Principles |edition=6th | publisher = Houghton Mifflin | year = 2009| isbn = 978-0-618-94690-7|page=A22}}</ref>
| Entropy = 210{{nbsp}}J/mol⋅K<ref name=b1/>
| HeatCapacity = 37{{nbsp}}J/mol⋅K
| DeltaGf = 13{{nbsp}}kJ/mol
 }}
|Section7={{Chembox Hazards
| ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics0694.htm ICSC 0694]
| GHSPictograms = {{GHS02}} {{GHS06}} {{GHS05}} {{GHS09}}
| HPhrases = 
| PPhrases = 
| NFPA-H = 4
| NFPA-F = 4
| NFPA-R = 2
| FlashPt = Flammable gas
| AutoignitionPtC = 38
| AutoignitionPt_notes = ''(see&nbsp;text)''
| ExploLimits = 1.79–98%<ref name=PGCH/>
| IDLH = 50{{nbsp}}ppm<ref name=PGCH>{{PGCH|0505}}</ref>
| LD50 = 3.03{{nbsp}}mg/kg (rat, oral)
| LC50 = 11{{nbsp}}ppm (rat, 4{{nbsp}}hr)<ref name=IDLH>{{IDLH|7803512|Phosphine}}</ref>
| REL = TWA 0.3{{nbsp}}ppm (0.4{{nbsp}}mg/m<sup>3</sup>), ST 1{{nbsp}}ppm (1{{nbsp}}mg/m<sup>3</sup>)<ref name=PGCH/>
| PEL = TWA 0.3{{nbsp}}ppm (0.4{{nbsp}}mg/m<sup>3</sup>)<ref name=PGCH/> 
| LCLo = 1000{{nbsp}}ppm (mammal, 5{{nbsp}}min)<br/>270{{nbsp}}ppm (mouse, 2{{nbsp}}hr)<br/>100{{nbsp}}ppm (guinea pig, 4{{nbsp}}hr)<br/>50{{nbsp}}ppm (cat, 2{{nbsp}}hr)<br/>2500{{nbsp}}ppm (rabbit, 20{{nbsp}}min)<br/>1000{{nbsp}}ppm (human, 5{{nbsp}}min)<ref name=IDLH/>
  }}
|Section8={{Chembox Related
| OtherCations = {{ubl|[[Ammonia]]|[[Arsine]]|[[Stibine]]|[[Bismuthine]]}}
| OtherCompounds = {{ubl|[[Trimethylphosphine]]|[[Triphenylphosphine]]|
[[Hydrogen sulfide]]}}
  }}
}}
'''Phosphine''' ([[IUPAC]] name: '''phosphane''') is a colorless, flammable, highly toxic compound with the [[chemical formula]] {{chem2|PH3|auto=yes}}, classed as a [[pnictogen hydride]]. Pure phosphine is odorless, but [[chemical purity|technical grade]] samples have a highly [[Odor#Types|unpleasant odor]] like rotting fish, due to the presence of [[substitution reaction|substituted]] phosphine and [[diphosphane]] ({{chem2|P2H4}}). With traces of {{chem2|P2H4}} present, {{chem2|PH3}} is spontaneously flammable in air ([[pyrophoric]]), burning with a luminous flame. Phosphine is a highly toxic respiratory poison, and is [[immediately dangerous to life or health]] at 50 ppm. Phosphine has a [[Trigonal pyramidal molecular geometry|trigonal pyramidal]] structure.

'''Phosphines''' are compounds that include {{chem2|PH3}} and the [[organophosphine]]s, which are derived from {{chem2|PH3}} by substituting one or more hydrogen atoms with organic groups.<ref name="goldbook phosphines">{{GoldBookRef|title=phosphines|file=P04553}}</ref> They have the general formula {{chem2|PH_{3−''n''}R_{''n''}|}}. '''Phosphanes''' are saturated phosphorus hydrides of the form {{chem2|P_{''n''}H_{''n''+2} }}, such as [[triphosphane]].<ref name="iupac phosphanes">{{GoldBookRef|title=phosphanes|file=P04548}}</ref> Phosphine ({{chem2|PH3}}) is the smallest of the phosphines and the smallest of the phosphanes.

==History==
Philippe Gengembre (1764–1838), a student of [[Lavoisier]], first obtained phosphine in 1783 by heating [[white phosphorus]] in an aqueous solution of [[potash]] (potassium carbonate).<ref>Gengembre  (1783) [https://archive.org/stream/mmoiresdemath10acad#page/651/mode/1up "Mémoire sur un nouveau gas obtenu, par l'action des substances alkalines, sur le phosphore de Kunckel"] (Memoir on a new gas obtained by the action of alkaline substances on Kunckel's phosphorus), ''Mémoires de mathématique et de physique'', '''10''' :  651–658.</ref><ref group=NB>For further information about the early history of phosphine, see:
*  ''The Encyclopædia Britannica'' (1911 edition), vol. 21, p. 480:  [https://books.google.com/books?id=Wto9AQAAMAAJ&pg=PA480 Phosphorus:  Phosphine.] {{Webarchive|url=https://web.archive.org/web/20151104205338/https://books.google.com/books?id=Wto9AQAAMAAJ&pg=PA480 |date=4 November 2015 }}
*  Thomas Thomson, ''A System of Chemistry'', 6th ed. (London, England:  Baldwin, Cradock, and Joy, 1820), vol. 1, [https://books.google.com/books?id=zU40AQAAMAAJ&pg=PA272 p. 272.] {{Webarchive|url=https://web.archive.org/web/20151104174911/https://books.google.com/books?id=zU40AQAAMAAJ&pg=PA272 |date=4 November 2015 }}</ref>

Perhaps because of its strong association with elemental [[phosphorus]], 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).<ref group=NB>Note:
*  [https://books.google.com/books?id=d2n7gY5SI2YC&pg=PA222 On p. 222] {{Webarchive|url=https://web.archive.org/web/20170424045509/https://books.google.com/books?id=d2n7gY5SI2YC&pg=PA222 |date=24 April 2017 }} 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, [https://books.google.com/books?id=d2n7gY5SI2YC&pg=PA216 on p. 216] {{Webarchive|url=https://web.archive.org/web/20170424085705/https://books.google.com/books?id=d2n7gY5SI2YC&pg=PA216 |date=24 April 2017 }}, 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" ([https://archive.org/details/b28754761/page/204 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" ([https://archive.org/details/b28754761/page/198 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.)</ref>

In 1844, [[Paul Thénard]], son of the French chemist [[Louis Jacques Thénard]], used a [[cold trap]] to separate diphosphine from phosphine that had been generated from [[calcium phosphide]], thereby demonstrating that {{chem2|P2H4}} is responsible for spontaneous flammability associated with {{chem2|PH3}}, and also for the characteristic orange/brown color that can form on surfaces, which is a polymerisation product.<ref>Paul Thénard (1844) [http://gallica.bnf.fr/ark:/12148/bpt6k2977n/f652.image.langEN "Mémoire sur les combinaisons du phosphore avec l'hydrogène"] {{Webarchive|url=https://web.archive.org/web/20151015161430/http://gallica.bnf.fr/ark:/12148/bpt6k2977n/f652.image.langEN |date=15 October 2015 }} (Memoir on the compounds of phosphorus with hydrogen), ''Comptes rendus'', '''18''' :  652–655.</ref> He considered diphosphine's formula to be {{chem2|PH2}}, and thus an intermediate between elemental phosphorus, the higher polymers, and phosphine. [[Calcium phosphide]] (nominally {{chem2|Ca3P2}}) produces more {{chem2|P2H4}} 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]]s ({{chem2|NR3}}).<ref group=NB>In 1857, [[August Wilhelm von Hofmann]] announced the synthesis of organic compounds containing phosphorus, which he named "[[trimethylphosphine]]" and "[[triethylphosphine]]", in analogy with "amine" (organo-nitrogen compounds), "arsine" (organo-arsenic compounds), and "stibine" (organo-antimony compounds).</ref><ref>{{cite journal |author1= A.W. Hofmann |author2= Auguste Cahours |year= 1857 |url= https://books.google.com/books?id=ZKkOAAAAIAAJ&q=phosphine&pg=PA523 |title= Researches on the phosphorus bases |journal= Proceedings of the Royal Society of London |number= 8 |pages= 523–527 |quote= (''From page 524:'')  The bases Me<sub>3</sub>P and E<sub>3</sub>P, the products of this reaction, which we propose to call respectively trimethylphosphine and triethylphosphine, ... |access-date= 19 November 2020 |archive-date= 10 February 2022 |archive-url= https://web.archive.org/web/20220210111914/https://books.google.com/books?id=ZKkOAAAAIAAJ&q=phosphine&pg=PA523 |url-status= live }}</ref> The gas {{chem2|PH3}} was named "phosphine" by 1865 (or earlier).<ref>William Odling, ''A Course of Practical Chemistry Arranged for the Use of Medical Students'', 2nd ed. (London, England:  Longmans, Green, and Co., 1865), [https://books.google.com/books?id=PQZZAAAAYAAJ&pg=PA227 pp. 227], 230.</ref>

==Structure and reactions==
{{chem2|PH3}} is a [[trigonal pyramid]]al molecule with ''C''<sub>3''v''</sub> [[molecular symmetry]]. The [[bond length|length]] of the P−H bond is 1.42&nbsp;[[angstrom|Å]], the H−P−H [[bond angle]]s are 93.5[[degree (angle)|°]]. The [[bond dipole moment|dipole moment]] is 0.58&nbsp;D, which increases with [[substitution (chemistry)|substitution]] of [[methyl group]]s in the series: {{chem2|CH3PH2}}, 1.10&nbsp;D; {{chem2|(CH3)2PH}}, 1.23&nbsp;D; {{chem2|(CH3)3P}}, 1.19&nbsp;D. In contrast, the dipole moments of amines decrease with substitution, starting with [[ammonia]], which has a dipole moment of 1.47&nbsp;D. The low dipole moment and almost orthogonal bond angles lead to the conclusion that in {{chem2|PH3}} the P−H bonds are almost entirely {{nowrap|pσ(P) – sσ(H)}} 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 [[Phosphorus-31 nuclear magnetic resonance|<sup>31</sup>P 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 general and lack of basicity in particular (p''K''<sub>aH</sub> = −14),<ref>{{Cite book|title=Introduction to Organic Chemistry|last1=Streitwieser|first1=Andrew|last2=Heathcock|first2=Clayton H. |last3=Kosower|first3=Edward M. |publisher=Medtech |edition=revised 4th |orig-date=1st ed. 1998|year=2017|isbn=978-93-85998-89-8|location=New Delhi|pages=828}}</ref> as well as an ability to form only weak [[hydrogen bonds]].<ref>{{ cite journal | last = Sennikov | first = P. G. | title = Weak H-Bonding by Second-Row (PH<sub>3</sub>, H<sub>2</sub>S) and Third-Row (AsH<sub>3</sub>, H<sub>2</sub>Se) Hydrides | journal = Journal of Physical Chemistry | year = 1994 | volume = 98 | issue = 19 | pages = 4973–4981 | doi = 10.1021/j100070a006 }}</ref>

The aqueous [[solubility]] of {{chem2|PH3}} is slight: 0.22&nbsp;cm<sup>3</sup> of gas dissolves in 1&nbsp;cm<sup>3</sup> of water. Phosphine dissolves more readily in [[solvent#Solvent classifications|non-polar solvents]] than in water because of the non-polar P−H bonds. It is technically [[Amphoterism|amphoteric]] in water, but acid and base activity is poor. Proton exchange proceeds via a [[phosphonium]] ({{chem2|PH4+}}) ion in acidic solutions and via [[phosphanide]] ({{chem2|PH2−}}) at high pH, with equilibrium constants ''K''<sub>b</sub> = {{val|4e-28}} and ''K''<sub>a</sub> = {{val|41.6e-29}}. Phosphine reacts with water only at high pressure and temperature, producing [[phosphoric acid]] and hydrogen:<ref name=":0">{{Cite report |url=https://uwaterloo.ca/giga-to-nanoelectronics-centre/sites/ca.giga-to-nanoelectronics-centre/files/uploads/files/phosphine-hydrogen.pdf |title=Material Safety Data Sheet: Phosphine/hydrogen Gas Mixture |date=8 September 2008 |publisher=Matheson Tri-Gas |access-date=4 July 2022 |archive-date=5 July 2022 |archive-url=https://web.archive.org/web/20220705191148/https://uwaterloo.ca/giga-to-nanoelectronics-centre/sites/ca.giga-to-nanoelectronics-centre/files/uploads/files/phosphine-hydrogen.pdf }}</ref><ref>{{Cite journal |last1=Rabinowitz |first1=Joseph |last2=Woeller |first2=Fritz |last3=Flores |first3=Jose |last4=Krebsbach |first4=Rita |date=November 1969 |title=Electric Discharge Reactions in Mixtures of Phosphine, Methane, Ammonia and Water |url=https://www.nature.com/articles/224796a0 |journal=Nature |language=en |volume=224 |issue=5221 |pages=796–798 |doi=10.1038/224796a0 |pmid=5361652 |bibcode=1969Natur.224..796R |s2cid=4195473 |issn=1476-4687|url-access=subscription }}</ref>

{{block indent|{{chem2|PH3 + 4 H2O}} {{Overset|pressure and<br />temperature|→}} {{Chem2|H3PO4 + 4 H2}}}}

Burning phosphine in the air produces [[phosphoric acid]]:<ref>{{Cite web |date=8 July 2021 |title=Phosphine: Lung Damaging Agent |url=https://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750035.html |access-date=4 July 2022 |location=United States |publisher=[[National Institute for Occupational Safety and Health]] (NIOSH) |language=en-us}}</ref><ref name=":0" />

{{block indent|{{chem2|PH3 + 2 O2}} {{Overset|150&nbsp;°C|→}} {{chem2|H3PO4}}.}}

==Preparation and occurrence==
Phosphine may be prepared in a variety of ways.<ref>{{ cite book | last = Toy | first = A. D. F. | title = The Chemistry of Phosphorus | publisher = Pergamon Press | location = Oxford, UK | year = 1973 }}</ref> Industrially it can be made by the reaction of white [[phosphorus]] with [[Sodium hydroxide|sodium]] or [[potassium hydroxide]], producing [[potassium hypophosphite|potassium]] or [[sodium hypophosphite]] as a by-product. 

{{block indent|{{chem2|3 KOH + P4 + 3 H2O → 3 KH2PO2 + PH3}}}}
{{block indent|{{chem2|3 NaOH + P4 + 3 H2O → 3 NaH2PO2 + PH3}}}}

Alternatively, the acid-catalyzed [[disproportionation]] of white [[phosphorus]] yields [[phosphoric acid]] 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 [[disproportionation]] of [[phosphorous acid]]:<ref>{{cite book |last1=Gokhale |first1=S. D. |last2=Jolly |first2=W. L. |title=Inorganic Syntheses |chapter=Phosphine |year=1967 |volume=9 |pages=56–58 |doi=10.1002/9780470132401.ch17|isbn=978-0-470-13168-8 }}</ref>

{{block indent|{{chem2|4 H3PO3 → PH3 + 3 H3PO4}}<br />
Phosphine evolution occurs at around 200&nbsp;°C.}}

Alternative methods include the hydrolysis of [[zinc phosphide]]:<ref>{{cite journal |doi=10.15227/orgsyn.098.0289 |title=Synthesis of tert-Alkyl Phosphines: Preparation of Di-(1-adamantyl)phosphonium Trifluoromethanesulfonate and Tri-(1-adamantyl)phosphine |date=2021 |last1=Barber |first1=Thomas |first2=Liam T.|last2=Baljournal=Organic Syntheses |journal=Organic Syntheses |volume=98 |pages=289–314 }}</ref>

{{block indent|{{chem2|Zn3P2 + 6 H2O → 3 Zn(OH)2 + 2 PH3}}}}

Some other metal phosphides could also be used, including [[aluminium phosphide]] or [[calcium phosphide]]. Pure samples of phosphine, free from {{chem2|P2H4}}, may be prepared using the action of [[potassium hydroxide]] on [[phosphonium iodide]]:

{{block indent|{{chem2|[PH4]I + KOH -> PH3 + KI + H2O}}}}

===Occurrence===
Phosphine is a worldwide constituent of the Earth's atmosphere at very low and highly variable concentrations.<ref>{{ cite journal |last1=Glindemann |first1=D. |last2=Bergmann |first2=A. |last3=Stottmeister |first3=U. | last4=Gassmann |first4=G.| title = Phosphine in the lower terrestrial troposphere | journal = Naturwissenschaften | year = 1996 | volume = 83 | issue = 3 | pages = 131–133 | doi = 10.1007/BF01142179 |bibcode = 1996NW.....83..131G |s2cid=32611695 }}</ref> It may contribute significantly to the global [[phosphorus cycle|phosphorus biochemical cycle]]. The most likely source is [[Reduction (chemistry)|reduction]] of [[phosphate]] in decaying organic matter, possibly via partial reductions and [[disproportionation]]s, since environmental systems do not have known reducing agents of sufficient strength to directly convert phosphate to phosphine.<ref>{{cite journal |last1=Roels |first1=J. |last2=Verstraete |first2=W. | title = Biological formation of volatile phosphorus compounds, a review paper | journal = Bioresource Technology | year = 2001 | volume = 79 | issue = 3 | pages = 243–250 | doi = 10.1016/S0960-8524(01)00032-3 | pmid = 11499578 }}</ref>

It is also found in [[Jupiter]]'s atmosphere.<ref>{{cite news |last1=Kaplan |first1=Sarah |title=The first water clouds are found outside our solar system – around a failed star |url=https://www.washingtonpost.com/news/speaking-of-science/wp/2016/07/11/the-first-water-clouds-are-found-outside-our-solar-system-around-a-failed-star/ |access-date=14 September 2020 |newspaper=The Washington Post |date=11 July 2016 |archive-date=15 September 2020 |archive-url=https://web.archive.org/web/20200915162551/https://www.washingtonpost.com/news/speaking-of-science/wp/2016/07/11/the-first-water-clouds-are-found-outside-our-solar-system-around-a-failed-star/ |url-status=live }}</ref>

====Possible extraterrestrial biosignature====
{{see also|Life on Venus}}
In 2020 a spectroscopic analysis was reported to show signs of phosphine in the [[atmosphere of Venus]] in quantities that could not be explained by known [[Abiotic component|abiotic processes]].<ref name=2020AsBio..20..235S>{{cite journal |title= Phosphine as a Biosignature Gas in Exoplanet Atmospheres |last1= Sousa-Silva |first1=Clara |last2=Seager |first2=Sara |last3=Ranjan |first3=Sukrit |last4=Petkowski |first4=Janusz Jurand |last5=Zhan |first5=Zhuchang |last6=Hu |first6=Renyu |last7=Bains |first7=William |publication-date= February 2020 |journal= Astrobiology |volume= 20 |number= 2 |date= 11 October 2019 |doi= 10.1089/ast.2018.1954 |bibcode= 2020AsBio..20..235S|pages= 235–268 |pmid= 31755740 |s2cid= 204401807 |arxiv= 1910.05224 }}</ref><ref name=NewsMIT-20191218>{{cite news |url= https://news.mit.edu/2019/phosphine-aliens-stink-1218 |title= A sign that aliens could stink |date= 18 December 2019 |work= MIT News |first= Jennifer |last= Chu |access-date= 14 September 2020 |archive-date= 18 February 2021 |archive-url= https://web.archive.org/web/20210218041422/https://news.mit.edu/2019/phosphine-aliens-stink-1218 |url-status= live }}</ref><ref name=SciNews-20191226>{{cite news |title= Phosphine Could Signal Existence of Alien Anaerobic Life on Rocky Planets |url= http://www.sci-news.com/astronomy/phosphine-biosignature-gas-07957.html |date= 26 December 2019 |newspaper= Sci-News |access-date= 15 September 2020 |archive-date= 14 September 2020 |archive-url= https://web.archive.org/web/20200914100028/http://www.sci-news.com/astronomy/phosphine-biosignature-gas-07957.html |url-status= live }}</ref> 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.<ref>{{cite journal|last1=Snellen|first1=I. A. G.|title=Re-analysis of the 267-GHz ALMA observations of Venus No statistically significant detection of phosphine|journal=Astronomy and Astrophysics|volume=644|page=L2|year=2020 
|arxiv=2010.09761 |bibcode=2020A&A...644L...2S|doi=10.1051/0004-6361/202039717|last2=Guzman-Ramirez|first2=L.|last3=Hogerheijde|first3=M. R.|last4=Hygate|first4=A. P. S.|last5=van der Tak|first5=F. F. S.|s2cid=224803085}}</ref><ref name=Thompson2020>{{cite journal|arxiv=2010.15188|title=The statistical reliability of 267 GHz JCMT observations of Venus: No significant evidence for phosphine absorption|year=2021|last1=Thompson|first1=M. A.|journal=Monthly Notices of the Royal Astronomical Society: Letters|volume=501|issue=1|pages=L18–L22|doi=10.1093/mnrasl/slaa187|doi-access=free |bibcode=2021MNRAS.501L..18T|s2cid=225103303}}</ref> The authors of the original study then claimed to detect it with a much lower concentration of 1&nbsp;ppb.<ref name=Greaves202011>{{cite journal|arxiv=2011.08176|title=Reply to: No evidence of phosphine in the atmosphere of Venus from independent analyses|year=2021|last1=Greaves|first1=Jane S.|last2=Richards|first2=Anita M. S.|last3=Bains|first3=William|last4=Rimmer|first4=Paul B.|last5=Clements|first5=David L.|last6=Seager|first6=Sara|last7=Petkowski|first7=Janusz J.|last8=Sousa-Silva|first8=Clara|last9=Ranjan|first9=Sukrit|last10=Fraser|first10=Helen J.|journal=Nature Astronomy|volume=5|issue=7|pages=636–639|doi=10.1038/s41550-021-01424-x|bibcode=2021NatAs...5..636G|s2cid=233296859}}</ref>{{Disputed inline|date=November 2021}}

==Applications==
===Organophosphorus chemistry===
Phosphine is a precursor to many [[organophosphorus compounds]]. It reacts with formaldehyde in the presence of [[hydrogen chloride]] to give [[tetrakis(hydroxymethyl)phosphonium chloride]], which is used in textiles. The [[hydrophosphination]] of alkenes is versatile route to a variety of phosphines. For example, in the presence of basic catalysts {{chem2|PH3}} adds of [[Michael acceptor]]s.  Thus with [[acrylonitrile]], it reacts to give [[tris(cyanoethyl)phosphine]]:<ref name=RussRev>{{cite journal|title=Phosphine in the Synthesis of Organophosphorus Compounds|first1=Boris A. |last1=Trofimov|first2=Svetlana N. |last2=Arbuzova|first3=Nina K. |last3=Gusarova|year=1999|journal=Russian Chemical Reviews|volume=68|issue=3 |pages=215–227 |doi=10.1070/RC1999v068n03ABEH000464|bibcode=1999RuCRv..68..215T |s2cid=250775640 }}</ref>

{{block indent|{{chem2|PH3 + 3 CH2\dCHZ → P(CH2CH2Z)3}} (Z is {{chem2|NO2}}, CN, or {{chem2|C(O)NH2}})}}

Acid catalysis is applicable to hydrophosphination with [[isobutylene]] and related analogues:

{{block indent|{{chem2|PH3 + R2C\dCH2 → R2(CH3)CPH2}}}}

where R is {{chem2|CH3}}, alkyl, etc.

===Microelectronics===
Phosphine is used as a [[dopant]] in the [[semiconductor]] industry, and a precursor for the deposition of [[compound semiconductor]]s. Commercially significant products include [[gallium phosphide]] and [[indium phosphide]].<ref>{{ Ullmann |last1=Bettermann |first=G. |last2=Krause |first2=W. |last3=Riess |first3=G. |last4=Hofmann |first4=T. | year = 2002 |  doi = 10.1002/14356007.a19_527 | title= Phosphorus Compounds, Inorganic | isbn = 3527306730 }}</ref>

===Fumigant (pest control)===
{{see also|Fumigation}}
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 [[agriculture|farm use]], pellets of [[aluminium phosphide]] (AlP), [[calcium phosphide]] ({{chem2|Ca3P2}}), or [[zinc phosphide]] ({{chem2|Zn3P2}}) 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 [[combustion|ignition]] or [[explosion]] of the released phosphine. 

An alternative is the use of phosphine gas itself which requires dilution with either {{chem2|CO2}} or {{chem2|N2}} 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.<ref name=DLD/>
<!--Historically [[sodium dihydrogen phosphide]] was used.<ref name=warner /> It was stored in sealed [[ampoule]]s prior to use.<ref name=warner>{{cite journal |last1=Warner  |first1=Mark S |last2=von Wandruszka  |first2=Ray |date=19 October 2023 |title=Urine on the Shelves Odious Materials in Archaeological Collections |url=https://www.cambridge.org/core/journals/advances-in-archaeological-practice/article/urine-on-the-shelves/885DFD7D55600C1DC594E4FAF6A1310D |journal=Advances in Archaeological Practice  |pages=1-8 |doi=10.1017/aap.2023.24 |access-date=14 November 2023|doi-access=free}}</ref> esoteric-->

==Toxicity and safety==
{{further|Aluminium phosphide poisoning}}
{{see also|White phosphorus munitions}}
Deaths have resulted from accidental exposure to fumigation materials containing [[aluminium phosphide]] or phosphine.<ref name="haaretz.com">{{cite news | url = https://www.haaretz.com/news/national/1.570036 | title = Two toddlers die after Jerusalem home sprayed for pests | newspaper = Haaretz | author1 = Ido Efrati | author2 = Nir Hasson | date = 22 January 2014 | access-date = 23 January 2014 | archive-date = 23 January 2014 | archive-url = https://web.archive.org/web/20140123064603/http://www.haaretz.com/news/national/1.570036 | url-status = live }}</ref><ref>{{cite web |language= es |url= http://www.rtve.es/noticias/20140203/familia-alcala-guadaira-murio-tras-inhalar-fosfina-unos-tapones/869841.shtml |title= La familia de Alcalá de Guadaíra murió tras inhalar fosfina de unos tapones |date= 3 February 2014 |publisher= Radio y Televisión Española |agency= EFE |website= RTVE.es |access-date= 23 July 2014 |archive-date= 2 March 2014 |archive-url= https://web.archive.org/web/20140302205408/http://www.rtve.es/noticias/20140203/familia-alcala-guadaira-murio-tras-inhalar-fosfina-unos-tapones/869841.shtml |url-status= live }}</ref><ref name=cbcth>{{cite news | url=http://www.cbc.ca/news/deaths-of-quebec-women-in-thailand-may-have-been-caused-by-pesticide-1.2569434 | title=Deaths of Quebec women in Thailand may have been caused by pesticide | date=13 March 2014 | publisher=CBC News | author=Julia Sisler | access-date=3 April 2017 | archive-date=4 April 2017 | archive-url=https://web.archive.org/web/20170404131909/http://www.cbc.ca/news/deaths-of-quebec-women-in-thailand-may-have-been-caused-by-pesticide-1.2569434 | url-status=live }}</ref><ref name=wp17>{{cite news|title=4 children killed after pesticide released toxic gas underneath their home, police say|url=https://www.washingtonpost.com/news/post-nation/wp/2017/01/03/4-children-killed-after-pesticide-released-toxic-gas-underneath-their-home-police-say/|access-date=6 January 2017|newspaper=Washington Post|author=Amy B Wang|date=3 January 2017|archive-date=25 June 2018|archive-url=https://web.archive.org/web/20180625161014/https://www.washingtonpost.com/news/post-nation/wp/2017/01/03/4-children-killed-after-pesticide-released-toxic-gas-underneath-their-home-police-say/|url-status=live}}</ref> It can be absorbed either by [[inhalation]] or [[transdermal]]ly.<ref name=haaretz.com/> As a respiratory poison, it affects the transport of oxygen or interferes with the utilization of oxygen by various cells in the body.<ref name=cbcth/> Exposure results in [[pulmonary edema]] (the lungs fill with fluid).<ref name=wp17/> Phosphine gas is heavier than air so it stays near the floor.<ref name=cbcfm>{{cite web | url = http://www.cbc.ca/news/canada/edmonton/pesticide-blamed-in-8-month-old-s-death-in-fort-mcmurray-1.2967286 | title = Pesticide blamed in 8-month-old's death in Fort McMurray | publisher = CBC News | date = 23 February 2015 | access-date = 23 February 2015 | archive-date = 24 February 2015 | archive-url = https://web.archive.org/web/20150224051710/http://www.cbc.ca/news/canada/edmonton/pesticide-blamed-in-8-month-old-s-death-in-fort-mcmurray-1.2967286 | url-status = live }}</ref>

Phosphine appears to be mainly a redox toxin, causing cell damage by inducing [[oxidative stress]] and mitochondrial dysfunction.<ref>{{cite journal |last1=Nath |first1=NS |last2=Bhattacharya |first2=I |last3=Tuck |first3=AG |last4=Schlipalius |first4=DI |last5=Ebert |first5=PR |title=Mechanisms of phosphine toxicity |journal=Journal of Toxicology |date=2011 |volume=2011 |article-number=494168 |doi=10.1155/2011/494168 |pmid=21776261|pmc=3135219 |doi-access=free }}</ref> Resistance in insects is caused by a mutation in a mitochondrial metabolic gene.<ref name=DLD/>

Phosphine can be absorbed into the body by inhalation. The main target organ of phosphine gas is the respiratory tract.<ref>{{cite web | url = https://www.cdc.gov/niosh/ershdb/EmergencyResponseCard_29750035.html | title = NIOSH Emergency Response Card | publisher = CDC | access-date = 6 April 2010 | archive-date = 2 October 2017 | archive-url = https://web.archive.org/web/20171002191640/https://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750035.html | url-status = live }}</ref> According to the 2009 U.S. [[National Institute for Occupational Safety and Health]] (NIOSH) pocket guide, and U.S. [[Occupational Safety and Health Administration]] (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&nbsp;ppm. The [[IDLH|Immediately Dangerous to Life or Health]] level is 50&nbsp;ppm. Overexposure to phosphine gas causes nausea, vomiting, abdominal pain, diarrhea, thirst, chest tightness, [[dyspnea]] (breathing difficulty), muscle pain, chills, stupor or syncope, and pulmonary edema.<ref>{{cite web | url = https://www.cdc.gov/niosh/npg/npgd0505.html | title = NIOSH pocket guide | publisher = CDC | date = 3 February 2009 | access-date = 6 April 2010 | archive-date = 11 May 2017 | archive-url = https://web.archive.org/web/20170511081428/https://www.cdc.gov/niosh/npg/npgd0505.html | url-status = live }}</ref><ref>{{cite web | url = http://www.inchem.org/documents/pds/pds/pest46_e.htm | title = WHO – Data Sheets on Pesticides – No. 46: Phosphine | website= Inchem.org | access-date = 6 April 2010 | archive-url = https://web.archive.org/web/20100218102324/http://www.inchem.org/documents/pds/pds/pest46_e.htm | archive-date = 18 February 2010 }}</ref> 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]].<ref>{{Cite report |url=https://www.cdc.gov/niosh/docs/99-126/ |title=NIOSH alert: preventing phosphine poisoning and explosions during fumigation. |date=1 September 1999 |publisher=CDC |doi=10.26616/nioshpub99126 |language=en-US |access-date=6 April 2010 |archive-date=19 June 2017 |archive-url=https://web.archive.org/web/20170619104259/https://www.cdc.gov/niosh/docs/99-126/ |url-status=live |doi-access=free }}</ref>

===Fumigation hazards===
Phosphine is used for [[pest control]], but its usage is strictly regulated due to high toxicity.<ref>{{cite web | last=Wallstén | first=Beata | title=Åklagaren bekräftar: Familjen i Söderhamn förgiftades av fosfin | website=[[Dagens Nyheter]] | date=13 February 2024 | url=https://www.dn.se/sverige/aklagaren-bekraftar-familjen-i-soderhamn-forgiftades-av-fosfin/ | language=sv | access-date=13 February 2024| archive-url=https://archive.today/20240213090046/https://www.dn.se/sverige/aklagaren-bekraftar-familjen-i-soderhamn-forgiftades-av-fosfin/| archive-date=13 February 2024}}</ref><ref>{{cite web | author=[[European Agency for Safety and Health at Work]] | title=Hälsorisker och förebyggande rutiner vid hantering av fumigerade containrar | url=https://osha.europa.eu/sites/default/files/845%20-%20SV.pdf | access-date=13 February 2024| archive-url=https://web.archive.org/web/20240213100055/https://osha.europa.eu/sites/default/files/845%20-%20SV.pdf| archive-date=13 February 2024}}</ref> Gas from phosphine has high mortality rate<ref>{{cite journal | last1=A Farrar | first1=Ross | last2=B Justus | first2=Angelo | last3=A Masurkar | first3=Vikram | last4=M Garrett | first4=Peter | title=Unexpected survival after deliberate phosphine gas poisoning: An Australian experience of extracorporeal membrane oxygenation rescue in this setting | journal=Anaesthesia and Intensive Care | volume=50 | issue=3 | date=2022 | issn=0310-057X | doi=10.1177/0310057X211047603 | pages=250–254| pmid=34871510 }}</ref> and has caused deaths in Sweden and other countries.<ref>{{cite news | title=Giftgåtan i Söderhamn: Gas tros ha dödat flickan | website=SVT Nyheter | date=13 February 2024 | url=https://www.svt.se/nyheter/lokalt/gavleborg/giftgatan-i-soderhamn-gas-tros-ha-dodat-flickan | language=sv | access-date=13 February 2024| archive-url=https://web.archive.org/web/20240213083312/https://www.svt.se/nyheter/lokalt/gavleborg/giftgatan-i-soderhamn-gas-tros-ha-dodat-flickan| archive-date=13 February 2024| last1=Berglin| first1=Rikard}}</ref><ref name="LJ p. ">{{cite journal | last=LJ | first=Willers-Russo | title=Three fatalities involving phosphine gas, produced as a result of methamphetamine manufacturing | journal=Journal of Forensic Sciences | date=1999 | publisher=J Forensic Sci | volume=44 | issue=3 | pages=647–652 | doi=10.1520/JFS14525J | issn=0022-1198 | pmid=10408124 }}</ref><ref name="Moirangthem Vidua Jahan Patnaik 2023 pp. 350–353">{{cite journal | last1=Moirangthem | first1=Sangita | last2=Vidua | first2=Raghvendra | last3=Jahan | first3=Afsar | last4=Patnaik | first4=Mrinal | last5=Chaurasia | first5=Jai | title=Phosphine Gas Poisoning | journal=American Journal of Forensic Medicine & Pathology | publisher=Ovid Technologies (Wolters Kluwer Health) | volume=44 | issue=4 | date=8 July 2023 | issn=1533-404X | doi=10.1097/paf.0000000000000855 | pages=350–353| pmid=37438888 }}</ref>

Because the previously popular [[fumigant]] [[methyl bromide]] has been phased out in some countries under the [[Montreal Protocol]], 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 [[pesticide resistance|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]] gene.<ref name=DLD>{{cite journal |last1=Schlipalius |first1=D. I. |last2=Valmas |first2=N. |last3=Tuck |first3=A. G. |last4=Jagadeesan |first4=R. |last5=Ma |first5=L. |last6=Kaur |first6=R. |date=2012 |title=A Core Metabolic Enzyme Mediates Resistance to Phosphine Gas |journal=Science |volume=338 |issue=6108 |pages=807–810 |doi=10.1126/science.1224951 |display-authors=etal |pmid=23139334 |bibcode=2012Sci...338..807S |s2cid=10390339}}</ref> 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.<ref name=":0" />

==In fiction==
[[Anne McCaffrey]]'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 (Breaking Bad)|pilot]] of the crime drama television series ''[[Breaking Bad]]'', [[Walter White (Breaking Bad)|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]].<ref>{{cite web |url=https://edu.rsc.org/analysis/breaking-bad-poisoning-gangsters-with-phosphine-gas/3007373.article |title=Breaking Bad – poisoning gangsters with phosphine gas |last=Hare |first=Jonathan |date=1 March 2011 |website=education in chemistry |publisher=Royal Society of Chemistry |archive-url=https://web.archive.org/web/20230924072242/https://edu.rsc.org/analysis/breaking-bad-poisoning-gangsters-with-phosphine-gas/3007373.article |archive-date=24 September 2023}}</ref>

==See also==
*[[Diphosphane]], {{chem2|H2P\sPH2}}, simplified to {{chem2|P2H4}}
*[[Diphosphene]], HP=PH

==Notes==
{{reflist|group=NB}}

==References==
{{Reflist}}

==Further reading==
* {{ cite journal | author = Fluck, E. | title = The Chemistry of Phosphine | journal = Topics in Current Chemistry | year = 1973 | volume = 35 | pages = 1–64 | doi = 10.1007/BFb0051358 | series = Fortschritte der Chemischen Forschung | isbn = 3-540-06080-4 | s2cid = 91394007 }}
* {{ cite book | author =[[World Health Organization]] | title = Phosphine and Selected Metal Phosphides | series = Environmental Health Criteria | publisher = Joint sponsorship of UNEP, ILO and WHO | location = Geneva | volume = 73 | year = 1988 | url = http://www.inchem.org/documents/ehc/ehc/ehc73.htm }}

==External links==
{{Commons category}}

* [http://www.inchem.org/documents/icsc/icsc/eics0694.htm International Chemical Safety Card 0694]<!-- Syntax: {{ICSC|AllDigits|TwoDigits}} -->
* [https://www.cdc.gov/niosh/topics/phosphine/ CDC – Phosphine – NIOSH Workplace Safety and Health Topic]

{{Chemical agents}}
{{Phosphorus compounds}}
{{Phosphides}}
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[[Category:Fumigants]]
[[Category:Functional groups]]
[[Category:Industrial gases]]
[[Category:Phosphorus hydrides]]
[[Category:Phosphorus(−III) compounds]]
[[Category:Blood agents]]
[[Category:Pyrophoric materials]]