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Phosphine
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Phosphine
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Phosphine
Skeletal formula of phosphine
Skeletal formula of phosphine
Ball-and-stick model of phosphine
Ball-and-stick model of phosphine
Spacefill model of phosphine
Spacefill model of phosphine
  Phosphorus, P
  Hydrogen, H
Names
IUPAC name
Phosphane
Other names
Hydrogen phosphide
Phosphamine
Phosphorus trihydride
Phosphorated hydrogen
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.029.328 Edit this at Wikidata
EC Number
  • 232-260-8
287
RTECS number
  • SY7525000
UNII
UN number 2199
  • InChI=1S/H3P/h1H3 checkY
    Key: XYFCBTPGUUZFHI-UHFFFAOYSA-N checkY
  • InChI=1/H3P/h1H3
    Key: XYFCBTPGUUZFHI-UHFFFAOYAP
  • P
Properties
PH3
Molar mass 33.99758 g/mol
Appearance Colourless gas
Odor odorless as pure compound; fish-like or garlic-like commercially[1]
Density 1.379 g/L, gas (25 °C)
Melting point −132.8 °C (−207.0 °F; 140.3 K)
Boiling point −87.7 °C (−125.9 °F; 185.5 K)
31.2 mg/100 ml (17 °C)
Solubility Soluble in alcohol, ether, CS2
slightly soluble in benzene, chloroform, ethanol
Vapor pressure 41.3 atm (20 °C)[1]
Conjugate acid Phosphonium (PH+4)
2.144
Viscosity 1.1×10−5 Pa⋅s
Structure
Trigonal pyramidal
0.58 D
Thermochemistry
37 J/mol⋅K
210 J/mol⋅K[2]
5 kJ/mol[2]
13 kJ/mol
Hazards
GHS labelling:
GHS02: Flammable GHS06: Toxic GHS05: Corrosive GHS09: Environmental hazard
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
4
4
2
Flash point Flammable gas
38 °C (100 °F; 311 K) (see text)
Explosive limits 1.79–98%[1]
Lethal dose or concentration (LD, LC):
3.03 mg/kg (rat, oral)
11 ppm (rat, 4 hr)[3]
1000 ppm (mammal, 5 min)
270 ppm (mouse, 2 hr)
100 ppm (guinea pig, 4 hr)
50 ppm (cat, 2 hr)
2500 ppm (rabbit, 20 min)
1000 ppm (human, 5 min)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 0.3 ppm (0.4 mg/m3)[1]
REL (Recommended)
 TWA 0.3 ppm (0.4 mg/m3), ST 1 ppm (1 mg/m3)[1]
IDLH (Immediate danger)
 50 ppm[1]
Safety data sheet (SDS) ICSC 0694
Related compounds
Other cations
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula PH3, classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting fish, due to the presence of substituted phosphine and diphosphane (P2H4). With traces of P2H4 present, 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 structure.

Phosphines are compounds that include PH3 and the organophosphines, which are derived from PH3 by substituting one or more hydrogen atoms with organic groups.[4] They have the general formula PH3−nRn. Phosphanes are saturated phosphorus hydrides of the form PnHn+2, such as triphosphane.[5] Phosphine (PH3) is the smallest of the phosphines and the smallest of the phosphanes.

History

[edit]

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).[6][NB 1]

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).[NB 2]

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 P2H4 is responsible for spontaneous flammability associated with PH3, and also for the characteristic orange/brown color that can form on surfaces, which is a polymerisation product.[7] He considered diphosphine's formula to be PH2, and thus an intermediate between elemental phosphorus, the higher polymers, and phosphine. Calcium phosphide (nominally Ca3P2) produces more 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 amines (NR3).[NB 3][8] The gas PH3 was named "phosphine" by 1865 (or earlier).[9]

Structure and reactions

[edit]

PH3 is a trigonal pyramidal molecule with C3v molecular symmetry. The length of the P−H bond is 1.42 Å, the H−P−H bond angles are 93.5°. The dipole moment is 0.58 D, which increases with substitution of methyl groups in the series: CH3PH2, 1.10 D; (CH3)2PH, 1.23 D; (CH3)3P, 1.19 D. In contrast, the dipole moments of amines decrease with substitution, starting with ammonia, which has a dipole moment of 1.47 D. The low dipole moment and almost orthogonal bond angles lead to the conclusion that in PH3 the P−H bonds are almost entirely 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 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 general and lack of basicity in particular (pKaH = −14),[10] as well as an ability to form only weak hydrogen bonds.[11]

The aqueous solubility of PH3 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 water, but acid and base activity is poor. Proton exchange proceeds via a phosphonium (PH+4) ion in acidic solutions and via phosphanide (PH−2) at high pH, with equilibrium constants Kb = 4×10−28 and Ka = 41.6×10−29. Phosphine reacts with water only at high pressure and temperature, producing phosphoric acid and hydrogen:[12][13]

PH3 + 4 H2O pressure and
temperature→ H3PO4 + 4 H2

Burning phosphine in the air produces phosphoric acid:[14][12]

PH3 + 2 O2 150 °C→ H3PO4.

Preparation and occurrence

[edit]

Phosphine may be prepared in a variety of ways.[15] Industrially it can be made by the reaction of white phosphorus with sodium or potassium hydroxide, producing potassium or sodium hypophosphite as a by-product.

3 KOH + P4 + 3 H2O → 3 KH2PO2 + PH3
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

[edit]

It is prepared in the laboratory by disproportionation of phosphorous acid:[16]

4 H3PO3 → PH3 + 3 H3PO4
Phosphine evolution occurs at around 200 °C.

Alternative methods include the hydrolysis of zinc phosphide:[17]

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 P2H4, may be prepared using the action of potassium hydroxide on phosphonium iodide:

[PH4]I + KOH → PH3 + KI + H2O

Occurrence

[edit]

Phosphine is a worldwide constituent of the Earth's atmosphere at very low and highly variable concentrations.[18] It may contribute significantly to the global phosphorus biochemical cycle. The most likely source is reduction of phosphate in decaying organic matter, possibly via partial reductions and disproportionations, since environmental systems do not have known reducing agents of sufficient strength to directly convert phosphate to phosphine.[19]

It is also found in Jupiter's atmosphere.[20]

Possible extraterrestrial biosignature

[edit]
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 processes.[21][22][23] 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.[24][25] The authors of the original study then claimed to detect it with a much lower concentration of 1 ppb.[26][disputed – discuss]

Applications

[edit]

Organophosphorus chemistry

[edit]

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 PH3 adds of Michael acceptors. Thus with acrylonitrile, it reacts to give tris(cyanoethyl)phosphine:[27]

PH3 + 3 CH2=CHZ → P(CH2CH2Z)3 (Z is NO2, CN, or C(O)NH2)

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

PH3 + R2C=CH2 → R2(CH3)CPH2

where R is CH3, alkyl, etc.

Microelectronics

[edit]

Phosphine is used as a dopant in the semiconductor industry, and a precursor for the deposition of compound semiconductors. Commercially significant products include gallium phosphide and indium phosphide.[28]

Fumigant (pest control)

[edit]
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 farm use, pellets of aluminium phosphide (AlP), calcium phosphide (Ca3P2), or zinc phosphide (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 ignition or explosion of the released phosphine.

An alternative is the use of phosphine gas itself which requires dilution with either CO2 or 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.[29]

Toxicity and safety

[edit]
Further information: Aluminium phosphide poisoning
See also: White phosphorus munitions

Deaths have resulted from accidental exposure to fumigation materials containing aluminium phosphide or phosphine.[30][31][32][33] It can be absorbed either by inhalation or transdermally.[30] As a respiratory poison, it affects the transport of oxygen or interferes with the utilization of oxygen by various cells in the body.[32] Exposure results in pulmonary edema (the lungs fill with fluid).[33] Phosphine gas is heavier than air so it stays near the floor.[34]

Phosphine appears to be mainly a redox toxin, causing cell damage by inducing oxidative stress and mitochondrial dysfunction.[35] Resistance in insects is caused by a mutation in a mitochondrial metabolic gene.[29]

Phosphine can be absorbed into the body by inhalation. The main target organ of phosphine gas is the respiratory tract.[36] 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 ppm. The Immediately Dangerous to Life or Health level is 50 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.[37][38] 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.[39]

Fumigation hazards

[edit]

Phosphine is used for pest control, but its usage is strictly regulated due to high toxicity.[40][41] Gas from phosphine has high mortality rate[42] and has caused deaths in Sweden and other countries.[43][44][45]

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

Explosiveness

[edit]

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.[12]

In fiction

[edit]

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 of the crime drama television series 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.[46]

See also

[edit]

Notes

[edit]

References

[edit]

Further reading

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Phosphine

View on Grokipedia
from Grokipedia
Phosphine (PH₃) is an consisting of one atom bonded to three atoms, forming the simplest member of the phosphine (phosphane) family of organophosphorus compounds. It exists as a colorless, flammable gas at , often exhibiting a distinctive - or decaying fish-like due to trace impurities, though pure phosphine is odorless. With a molecular weight of 34.00 g/mol, phosphine has a arising from the sp³ hybridization of the central atom and its of electrons, resulting in P-H bond lengths of approximately 1.42 Å and H-P-H bond angles of about 93.5°. Phosphine is highly reactive and unstable in air, capable of spontaneous ignition above 100 °C or under certain conditions, and it decomposes into its elements when heated. Its physical properties include a of -87.7 °C and a of -133.8 °C, with low in (approximately 310 mg/L at 17 °C) but greater solubility in organic solvents like . Chemically, it acts as a and , and it can form adducts with Lewis acids or undergo substitution reactions to produce more complex phosphines used in and coordination chemistry. The compound is produced industrially by of metal s, such as aluminum or calcium , or through acid treatment of , and it is commonly prepared in laboratories by heating white with aqueous solution in an inert atmosphere. Primary applications include its use as a fumigant and for protecting stored grains, animal feeds, and from pests, where it is released from tablets. In the , phosphine serves as a precursor for doping in semiconductors to create n-type materials essential for microchips and solar cells. Phosphine is extremely toxic, primarily affecting the respiratory and cardiovascular systems through , with an immediately dangerous to life or (IDLH) concentration of 50 ppm and a lethal concentration for 50% of exposed rats (LC50) of around 10-20 ppm over 4 hours. Exposure causes symptoms ranging from irritation and nausea to and , necessitating strict handling protocols including ventilation and . In natural settings, phosphine occurs in anaerobic microbial processes, such as in swamps or , where it is produced by certain reducing . Astronomically, it is a component of the atmospheres of gas giants like and Saturn, formed under high-pressure conditions, and was tentatively detected in Venus's cloud decks in 2020 at levels suggesting non-equilibrium chemistry—possibly biological—though subsequent observations, including those from the telescope in 2022, have not confirmed its presence there. More recently, in 2025, phosphine was identified in the atmosphere of a , marking the first such detection in a substellar object and providing insights into chemistry in cool astronomical environments.

Properties

Molecular structure

Phosphine has the PH₃ and a molecular weight of 33.997 g/mol. The molecule exhibits a trigonal pyramidal with C_{3v} symmetry, arising from the central atom bonded to three atoms and possessing one of electrons. According to valence shell electron pair repulsion (, phosphine is classified as an AX₃E , where the lone pair occupies more space than the bonding pairs, leading to a compressed structure relative to an ideal tetrahedral arrangement. Experimental measurements determine the P-H to be approximately 1.42 Å and the H-P-H to be ≈93.5°, significantly smaller than the 109.5° expected for sp³ hybridization due to the minimal hybridization of 's 3s and 3p orbitals—the bonds form primarily from pure p orbitals, with the residing mostly in the 3s orbital. In comparison to (NH₃), which shares a similar trigonal pyramidal shape but with a of 107° and a dipole moment of 1.47 D, phosphine displays lower polarity, evidenced by its dipole moment of 0.58 D; this reduced polarity stems from the smaller electronegativity difference between and (0.01 on the Pauling scale) compared to and (0.84), as well as the larger atomic size of , which diffuses the charge separation. Spectroscopic characterization confirms the structure: infrared spectroscopy reveals P-H stretching modes at 2321 cm⁻¹ (A₁ symmetry) and 2327 cm⁻¹ (E symmetry), while the ³¹P NMR chemical shift appears at -240 ppm relative to external 85% H₃PO₄, reflecting the electron-rich environment around the phosphorus nucleus.

Physical properties

Phosphine (PH₃) is a colorless gas at room temperature and atmospheric pressure, exhibiting a characteristic garlic-like odor due to impurities (pure phosphine is odorless). Its boiling point is -87.7 °C, and its melting point is -133.8 °C. The density of phosphine gas is 1.52 g/L at 0 °C and 1 atm (STP). Phosphine shows limited solubility in water, approximately 35 mg/L at 20 °C, but it is more soluble in organic solvents such as ethanol. The compound exhibits thermal instability, decomposing above 200 °C into phosphorus and hydrogen gas. Thermodynamic parameters include a (ΔH_f°) of +5.4 kJ/mol and a of formation (ΔG_f°) of +13.4 kJ/mol at 298 .

Chemical reactivity

(PH₃) exhibits Lewis base behavior due to the presence of a on the atom, enabling it to form coordination complexes with Lewis acids. For instance, it readily forms adducts such as PH₃·BH₃ and Cl₃Al·PH₃, where the phosphorus lone pair donates electrons to the empty orbital of the or aluminum center. Oxidation of phosphine occurs readily in the presence of oxygen, leading to the formation of phosphorus oxides. The balanced reaction is 2PH₃ + 4O₂ → P₂O₅ + 3H₂O, reflecting the conversion of from the -3 to +5. Phosphine is highly flammable and autoignites in air above approximately 100°C, particularly if impure with traces of diphosphine (P₂H₄), though pure samples require temperatures above 150°C. Hydrolysis of phosphine proceeds slowly with water to yield hypophosphorous acid and hydrogen gas, as represented by the equation PH₃ + 2H₂O → H₃PO₂ + 2H₂; this reaction is catalyzed by bases, enhancing the rate of decomposition. Phosphine undergoes substitution reactions with hydrogen halides to form phosphonium salts. A representative example is PH₃ + HBr → PH₄⁺ Br⁻, where the lone pair on phosphorus accepts a proton, resulting in a tetrahedral phosphonium cation. Thermal decomposition of phosphine at elevated temperatures yields white and : 4PH₃ → P₄ + 6H₂. This reaction is catalyzed by metal surfaces such as or . In comparison to , phosphine displays significantly weaker basicity, with a pK_b of approximately 28 versus 4.75 for NH₃, attributable to the poorer orbital overlap of the phosphorus with protons due to its larger size and lower .

Synthesis

Laboratory preparation

Phosphine is commonly prepared in settings through small-scale reactions that prioritize , given its , flammability, and tendency to autoignite in air. These methods are typically performed under inert atmospheres, such as or , to prevent oxidation or combustion, and often yield 70-90% based on the when optimized. A classic approach involves the of metal phosphides, such as aluminum phosphide, with water. The reaction proceeds as follows: \ceAlP+3H2O−>Al(OH)3+PH3\ce{AlP + 3H2O -> Al(OH)3 + PH3} This method generates phosphine gas quantitatively at room temperature upon addition of water to the phosphide, often in a controlled apparatus to capture the evolved gas; similar hydrolysis occurs with calcium phosphide (Ca₃P₂ + 6H₂O → 3Ca(OH)₂ + 2PH₃). Phosphine can also be synthesized from white phosphorus reacted with aqueous potassium hydroxide under anaerobic conditions: \ceP4+3KOH+3H2O−>3KH2PO2+PH3\ce{P4 + 3KOH + 3H2O -> 3KH2PO2 + PH3} Heating the mixture to 70-80°C in a flask flushed with inert gas facilitates the disproportionation, with the phosphine distilled off as it forms; this method typically affords 70-85% yield, though side products like hydrogen may form if oxygen is present. Purification of the crude phosphine gas commonly involves fractional distillation at low temperatures (-60°C to -100°C) under reduced pressure or preparative gas chromatography to separate it from impurities such as diphosphine (P₂H₄) or unreacted phosphorus compounds, ensuring high purity (>95%) for subsequent use.

Industrial production

The primary industrial methods for phosphine production involve the reaction of white (P₄) with aqueous alkali, such as , under inert conditions to produce phosphine and : \ceP4+3NaOH+3H2O−>3NaH2PO2+PH3\ce{P4 + 3NaOH + 3H2O -> 3NaH2PO2 + PH3} Alternatively, white is heated under pressure in acidified (with ) at approximately 550 K (277°C) in reactors. These processes yield phosphine that requires purification to remove impurities such as diphosphine (P₂H₄). White used in these methods is typically derived from phosphate ores processed in furnaces, where phosphate rock, coke, and silica are smelted to produce elemental vapor that is condensed into the white allotrope. For fumigation applications, is generated by of metal s (e.g., aluminum or calcium phosphide), integrating production with end-use to minimize handling of the pure gas. For high-purity needs in , specialized routes like electrochemical reduction of derivatives or low-temperature plasma activation of with are employed, offering improved purity and efficiency. As of 2025, emerging sustainable methods include clean of P₄ using industrially common without toxic byproducts or waste. Global phosphine output is estimated at approximately 1,500 tonnes per year (as of the early 2020s), driven by demand in and , with major producers including Syensqo (formerly Solvay) and Nippon Chemical Industrial Co., Ltd. Syensqo specializes in high-purity cylinderized phosphine for electronic grades, while Nippon Chemical is one of the few global suppliers of liquefied high-purity phosphine, leveraging over 30 years of expertise in phosphine technology. Due to phosphine's high and flammability ( around 100°C), industrial production incorporates closed-loop systems with automated monitoring, purging, and explosion-proof enclosures to contain emissions and prevent ignition. These integrations comply with international standards, ensuring worker protection and environmental containment during synthesis and storage.

Occurrence

Terrestrial sources

Phosphine occurs on Earth primarily through natural geological and biological processes, as well as anthropogenic activities, though its concentrations remain trace in most environments. Geological sources involve the of rare minerals, such as those found in basaltic and formations, which can release phosphine under acidic or aqueous conditions. For instance, natural phosphides identified in the region of demonstrate potential as atmospheric phosphine precursors via reactions with or mild acids. Volcanic emissions and hot springs contribute negligible amounts, as Earth's volcanic activity is not a significant phosphine source compared to biological pathways, with trace releases possibly stemming from impurities in or hydrothermal fluids. Biological production of phosphine arises mainly from microbial reduction of in anaerobic environments, such as sediments, wetlands, and animal waste. Anaerobic , including species like and , facilitate this process by utilizing organic carbon as an to reduce (PO₄³⁻) to phosphine (PH₃), often in oxygen-deprived sediments or . This bioreductive mechanism accounts for a substantial portion of natural phosphine emissions, with production enhanced by high availability and reducing conditions in environments like rice paddies or intestinal tracts. Anthropogenic sources generate as an unintended byproduct during involving compounds. In , of by phosphate-reducing microbes produces , with emissions observed in plants and systems. Metallurgical operations, such as synthesis from containing impurities or iron processing with contaminants, release through . production, particularly during the handling of rock or manufacturing, can emit trace from partial reduction or impurity reactions, though this is minimized in modern facilities. In Earth's atmosphere, phosphine persists at low global concentrations, typically below 0.001 (ppb), with remote tropospheric levels ranging from 0.03 to 1.5 parts per trillion (ppt) (equivalent to 0.04–2.03 ng/m³) based on measurements. Local elevations occur in polluted or biogenic hotspots, such as gases, reflecting microbial activity in . These levels highlight phosphine's role as a minor component of the , influenced more by biological and human sources than geological ones. Detection of phosphine in terrestrial samples relies on sensitive analytical techniques, with gas chromatography-mass spectrometry (GC-MS) being the standard method for quantifying trace amounts. This approach involves headspace sampling to volatilize phosphine, followed by chromatographic separation and mass spectrometric identification, enabling detection limits in the ppb to ppt range for air, , or matrices.

Extraterrestrial detection

Phosphine has been detected in the atmospheres of the planets and Saturn through . Voyager 1's Infrared Interferometer Spectrometer (IRIS) observations in 1979 confirmed the presence of phosphine in Jupiter's upper , with mixing ratios estimated at approximately 1 part per million (ppm) at pressures of 2-4 bars. Similar Voyager IRIS data for Saturn indicated phosphine abundances of around 0.7-1 ppm in the upper , consistent with vertical mixing from deeper layers where it forms. These detections highlighted phosphine's role as a tracer for atmospheric dynamics, as its observed levels exceed equilibrium expectations due to from the planet's interiors. Phosphine was tentatively detected in the cloud decks of in at levels of about 20 ppb, suggesting possible non-equilibrium chemistry potentially of biological origin, though subsequent observations, including those from the telescope in 2022, have not confirmed its presence. In the , phosphine was first confirmed in 2024 through radio observations of absorption lines toward stars, revealing its presence in diffuse circumstellar envelopes. The detection utilized the J=1-0 rotational transition at approximately 266.94 GHz, indicating column densities on the order of 10^{12} cm^{-2} in these regions. This marks phosphine as a key -bearing molecule in the , likely formed through gas-phase ion-molecule reactions involving phosphorus hydrides in reducing environments. A notable recent detection occurred in 2025 using the (JWST) to observe the atmosphere of the cold Wolf 1130C. Spectroscopy revealed phosphine absorption features at 4.3 μm, yielding an abundance of 0.1 ppm (100 ppb), or roughly 10^{-7}, consistent with disequilibrium chemistry models for and Saturn and indicating strong vertical mixing from interior sources. In such objects, phosphine forms geochemically in the deep, high-pressure interior through reactions of with , then is transported upward before partial photochemical destruction in the layers. For and Saturn, analogous mechanisms prevail: geochemical synthesis in reducing, high-temperature interiors followed by convective dredging to the , where photolysis limits its lifetime to days to years.

History

Discovery

Phosphine was first prepared in 1783 by the French chemist Philippe Gengembre, a student of , through the heating of white in an aqueous solution of (potash). This early preparation produced an impure gas that spontaneously ignited. The gas was isolated as a pure compound in 1812 by British chemist Sir , who obtained it by reacting water with calcium phosphide (Ca₃P₂), a method that yielded cleaner samples and allowed for more accurate characterization. Davy noted its spontaneous flammability, attributing it to trace impurities of diphosphine (P₂H₄), and described its garlic-like odor and toxicity, observing that it caused severe respiratory distress in experimental animals. Early studies, including those by Davy, highlighted confusion between phosphine and related phosphorus hydrides, often referred to collectively as "phosphoretted hydrogen," complicating efforts to define its exact composition. In 1857, German chemist August Wilhelm von Hofmann synthesized the first organophosphorus compounds, such as , and coined the name "phosphine" for PH₃ and its organic analogs (PR₃), drawing an analogy to the family of nitrogen compounds (NR₃). Hofmann's work emphasized its basic properties and reactivity, solidifying its recognition as PH₃. The pyramidal structure of phosphine was first inferred in the through valence theory, which predicted a trigonal pyramidal geometry similar to but with wider bond angles due to phosphorus's larger size and poorer orbital overlap. This was confirmed experimentally in 1959 via gas-phase , which measured the P-H as approximately 1.42 Å and the H-P-H as 93.5°. Early controversies centered on the gas's purity and composition, with mixtures of phosphine and diphosphine often mistaken for a single entity under the term "phosphoretted hydrogen." Toxicity was recognized soon after isolation; by the 1840s, industrial accidents involving match production exposed workers to phosphine fumes, causing symptoms like , , and death, prompting initial safety warnings in chemical literature.

Key developments

During in the 1940s, phosphine generated from aluminum phosphide tablets was adopted as an industrial fumigant for grain storage in and allied efforts, providing an effective alternative to earlier liquid fumigants amid wartime shortages. This marked a significant advancement in for stored commodities, leveraging phosphine's rapid diffusion and low residue properties. In the , the development of , RhCl(PPh₃)₃, revolutionized by incorporating ligands, enabling efficient of alkenes under mild conditions and sparking a boom in phosphine-based ligand chemistry for industrial processes. This breakthrough, reported between 1965 and 1967, laid the foundation for chiral phosphine variants and , influencing subsequent advancements in . The 1970s saw the first spectroscopic confirmation of phosphine in planetary atmospheres, notably through observations of in 1977, which revealed PH₃ as a key component influencing the planet's tropospheric chemistry. Retrospective analysis of data from NASA's Pioneer Venus mission in 1978 has suggested potential phosphine presence in Venusian clouds (as of 2021), though the original analyses focused on broader atmospheric composition. In September 2020, tentative detection of phosphine in 's cloud decks at ~20 parts per billion was reported using the James Clerk Maxwell Telescope (JCMT) and Atacama Large Millimeter/submillimeter Array (ALMA), igniting global scientific interest in potential biological or exotic chemical processes on the planet. Recent 2024 peer-reviewed studies have refuted proposed abiotic sources for Venusian phosphine, such as and , concluding that known mechanisms cannot account for observed levels in the planet's oxidizing atmosphere. Concurrently, planning for the UK-led (Venus Explorer for Reduced Vapours in the Environment) mission advanced in 2025, aiming to directly analyze phosphine and other reduced gases in 's clouds via a low-cost probe to resolve ongoing debates. In October 2025, phosphine was detected in the atmosphere of a for the first time, providing new insights into chemistry in cool substellar environments.

Astrobiological significance

Biosignature hypothesis

Phosphine (PH₃) has emerged as a biosignature gas due to its association with biological processes on , where it is primarily produced by anaerobic microorganisms through the reduction of or phosphite compounds in oxygen-poor environments, such as sediments and the guts of certain animals. Abiotic production of phosphine on is minimal and typically occurs only under extreme conditions, like high-temperature or strikes, but does not account for observed environmental levels. In contrast, models of Venus's atmosphere predict that abiotic mechanisms, including photochemical reactions and thermochemical equilibrium, would yield phosphine abundances below 10⁻¹⁰ relative to oxidized phosphorus species like (H₃PO₄) in the decks. The hypothesis gained prominence with the detection of phosphine in Venus's atmosphere at approximately 20 (ppb) in the cloud layers between 50 and 60 km altitude, a region considered potentially habitable due to moderate temperatures and pressures. This abundance is inconsistent with known Venusian , where is expected to exist predominantly in oxidized forms amid the planet's sulfuric acid-rich, oxidizing environment, making sustained phosphine presence anomalous without an active replenishment source. Alternative abiotic explanations, such as reactions involving chemistry (e.g., misidentification with SO₂ spectral lines) or volcanic of phosphides that hydrolyze to phosphine, have been proposed but face significant challenges. Simulations indicate that volcanic rates on would need to be extraordinarily high—far exceeding current estimates of planetary activity—to produce detectable phosphine levels, with 2024 modeling showing production rates too slow to sustain even 1 ppb against atmospheric destruction processes like photolysis and oxidation. These abiotic pathways thus struggle to explain the observed disequilibrium without invoking unknown geochemical processes. In the broader astrobiological context, phosphine serves as a disequilibrium indicator in habitable zones, signaling the presence of reduced gases that require ongoing biological or exotic abiotic input to persist against rapid atmospheric removal, much like methane (CH₄) on Mars, where trace levels suggest potential microbial activity or subsurface geology.

Recent observations and missions

Following the initial 2020 detection of phosphine in Venus's atmosphere, subsequent reanalyses from 2021 to 2023 yielded mixed results. Observations using the James Clerk Maxwell Telescope (JCMT), building on Infrared Telescope Facility data, confirmed the presence of phosphine but at a significantly lower abundance of approximately 1 part per billion (ppb) in the cloud decks, compared to the original estimate of around 20 ppb. In contrast, the Stratospheric Observatory for Infrared Astronomy (SOFIA) reported a non-detection in 2022, establishing a strict upper limit below 0.1 ppb, though later reprocessing of these spectra suggested a possible trace amount of about 3 ppb after accounting for contaminating signals like sulfur dioxide. A 2024 review in Frontiers in Astronomy and Space Sciences examined potential abiotic production mechanisms for phosphine on , including gas-phase reactions, , , and subsurface , but concluded that no viable non-biological source could explain the observed levels, emphasizing the need for in-situ probes to resolve the discrepancy. In 2025, the (JWST) confirmed undepleted phosphine in the atmosphere of the Wolf 1130C, marking the first such detection in a substellar object and suggesting possible abiotic formation pathways under reducing conditions. Planned missions aim to address these uncertainties through direct sampling and mapping. The UK-led (Venus Explorer for Reduced Vapours in the Environment) probe, proposed for launch in the 2030s as a companion to ESA's orbiter, would analyze atmospheric gases at multiple altitudes to detect phosphine and other potential biosignatures like . itself, scheduled for a 2031 launch (with arrival around 2033), includes the VenSpec infrared spectrometer suite to map trace gases, including phosphine, across Venus's atmosphere from . Complementing these, ongoing ground-based efforts like the JCMT-Venus Legacy Survey continue to monitor phosphine for seasonal and diurnal variations, providing baseline data over multi-year cycles to contextualize mission findings.

Applications

Organic synthesis

Phosphine (PH₃) and its derivatives serve as versatile precursors and reagents in the synthesis of organophosphorus compounds, which are essential in pharmaceuticals, agrochemicals, and . These compounds leverage the nucleophilic properties of trivalent phosphorus to form P-C bonds, enabling the construction of complex molecular architectures. Key transformations involving phosphine derivatives include the formation of phosphonates, ylides for olefin synthesis, and ligands for transition-metal catalysis, often achieving high efficiency and selectivity. A prominent application is the Michaelis-Arbuzov reaction, where trialkyl phosphites, prepared from and alcohols—react with alkyl s to yield dialkyl alkylphosphonates. In this process, the phosphite acts as a , attacking the alkyl to form a phosphonium intermediate, which then rearranges with departure to produce the phosphonate . For example, ((EtO)₃P) reacts with methyl iodide (CH₃I) to give diethyl methylphosphonate ((EtO)₂P(O)CH₃) and ethyl iodide (EtI), typically in high yields under conditions without additional catalysts. This reaction is widely employed for synthesizing phosphonate precursors to herbicides and inhibitors, offering broad substrate scope for primary and secondary alkyl s. Phosphine derivatives also play a central role in the , where triarylphosphines such as (PPh₃)—accessible through substitution reactions involving phosphine—form salts that deprotonate to for synthesis. The , generated by treating the salt (e.g., Ph₃P⁺CH₂R X⁻) with a base, reacts with aldehydes or ketones to afford and oxide (Ph₃P=O) as a . This olefination is stereoselective, often favoring Z- under salt-free conditions, and is indispensable for constructing carbon-carbon double bonds in synthesis, with yields exceeding 80% for stabilized ylides. In catalytic applications, , derived from phosphine through oxidation to followed by arylation, forms stable complexes with transition metals, enhancing reactivity in cross-coupling reactions. A seminal example is the , where tetrakis(triphenylphosphine)palladium(0) (Pd(PPh₃)₄) catalyzes the coupling of aryl halides with alkenes in the presence of a base, producing substituted styrenes via syn-addition and β-hydride elimination. This stabilizes the Pd(0)/Pd(II) cycle, enabling high turnover numbers (up to 10⁶) and broad scope for electron-rich and -poor substrates, with typical yields of 70-95% under mild conditions. Recent advances have expanded phosphine's utility in photoredox catalysis, particularly through visible-light-mediated C-C bond formations. A 2024 review highlights phosphine-mediated protocols where tertiary phosphines act as reductants or catalysts under blue LED irradiation, facilitating radical additions and couplings with high . For instance, phosphines enable the deoxygenative coupling of alcohols with alkenes, achieving C-C bonds in 60-90% yields without metal catalysts. These methods emphasize and compatibility with complex molecules. Phosphine-based ligands further enable asymmetric synthesis, imparting high in chiral transformations. P-stereogenic phosphines, synthesized via stereoselective substitutions on phosphine scaffolds, serve as ligands in enantioselective hydrogenations and allylations, often delivering products with >95% . This stereocontrol arises from the ligands' ability to create asymmetric environments around metal centers, as demonstrated in rhodium-catalyzed conjugate additions yielding enantioenriched phosphine oxides. Such applications underscore phosphine's impact on producing optically active organophosphorus compounds for .

Microelectronics

Phosphine plays a crucial role as a doping agent in , particularly in the fabrication of n-type semiconductors, where it introduces atoms into substrates to enhance electrical conductivity. During (CVD), phosphine decomposes thermally, following the reaction PH3→P+32H2\text{PH}_3 \rightarrow \text{P} + \frac{3}{2} \text{H}_2 at approximately 600°C, enabling the incorporation of into the silicon lattice for precise control of carrier concentration. This process forms n-type semiconductors by donating excess electrons from atoms, with concentrations typically ranging from 101510^{15} to 102010^{20} atoms/cm³ to achieve desired resistivity levels in devices such as transistors and integrated circuits. In low-pressure CVD (LPCVD) or metal-organic CVD (MOCVD) systems, is combined with as the primary precursor, requiring electronic-grade phosphine with purity greater than 99.999% (5N) to minimize impurities and ensure high-quality epitaxial layers. The demand for phosphine in manufacturing is fueling market expansion, with projections indicating a CAGR of approximately 7% for the phosphine gas market, including electronic-grade, from 2024 onward, attributed to surging needs for advanced chips in and . While serves as an alternative for doping in certain high-mobility applications, phosphine is generally favored for doping due to its comparatively lower toxicity profile.

Fumigation

Phosphine is widely employed as a fumigant in and storage facilities to control stored-product pests, penetrating deeply into commodities and structures to eradicate infestations without leaving significant residues. Its primary mechanism of action involves inhibiting , a key enzyme in the mitochondrial , which disrupts and leads to asphyxiation in . Common formulations include solid aluminum phosphide tablets or pellets, such as Phostoxin, which react with atmospheric moisture to generate phosphine gas on-site, enabling controlled release during application. These formulations are typically applied in sealed grain silos, warehouses, and shipping containers, with recommended dosages of 1-3 g/m³ of phosphine for exposure periods of 5-7 days to achieve effective under standard conditions. As a toxic fumigant gas deliberately generated for insect control in grain storage such as silos, phosphine requires thorough aeration post-application to dissipate residual concentrations, which can otherwise linger and pose severe health risks if management protocols are inadequate. The global grain fumigants market, dominated by phosphine-based products, was valued at approximately USD 1.45 billion in 2025, with a projected CAGR of 5.9% from 2025 to 2030, largely driven by stringent international regulations requiring pest-free commodities. Phosphine demonstrates high , achieving over 99% mortality rates against common stored-product pests like the (Sitophilus oryzae) and lesser grain borer ( dominica) when applied at sufficient concentrations and durations. However, resistance is emerging in several species, including the (Tribolium castaneum) and sawtoothed grain beetle (), complicating management in regions with repeated exposures. Due to phosphine's flammability, operations must monitor gas concentrations to avoid risks during application.

Safety and toxicity

Health effects

Phosphine is highly toxic upon acute exposure, with an LC50 of 11 ppm over 4 hours in rats, classifying it among the most potent gaseous toxins. Initial symptoms in humans include , , , , and , progressing to severe respiratory distress with in higher exposures. In extreme cases, exposure can lead to and death due to multi-organ failure. The primary mechanism of phosphine toxicity involves disruption of cellular energy production by inhibiting cytochrome c oxidase (complex IV) in the mitochondrial , which halts and triggers the generation of and free radicals. This oxidative stress exacerbates tissue damage across organs, particularly in the lungs, heart, and liver. Chronic exposure to low levels of phosphine can result in liver and kidney damage, as observed in where subchronic led to histopathological changes and reduced organ function. To mitigate these risks, the (OSHA) has established a (PEL) of 0.3 ppm as an 8-hour time-weighted average. In the 2020s, incidents involving phosphine have demonstrated its lethal potential in confined spaces. For instance, a 2021 maritime event resulted in at least one death among crew members due to phosphine accumulation, while a 2024 apartment in the poisoned a family, leading to a child's fatality.

Explosive risks

Phosphine poses significant risks due to its high flammability and ability to form detonable mixtures with air or oxygen. The gas has a wide flammable range, with a lower limit of approximately 1.8% by volume in air and an upper limit of 98%, allowing ignition across a broad concentration spectrum. Its for pure phosphine is around 100°C, though commercial samples often ignite at lower temperatures, such as 38°C, due to impurities like diphosphine (P₂H₄). Detonation hazards arise from phosphine's formation of shock-sensitive mixtures with oxygen, particularly in liquefied form, where its endothermic nature (standard heat of formation +22.8 kJ/mol, equivalent to about 0.67 kJ/g) enables powerful upon initiation. These mixtures can propagate as rather than mere deflagrations under confined conditions. Explosivity is exacerbated by catalytic factors, including traces of diphosphine or certain metals that lower ignition thresholds, and humid environments, which can reduce the effective lower explosive limit by accelerating reactive . For instance, in settings promotes the generation of impure phosphine, heightening risks. Notable incidents in the 2010s underscore these dangers, such as the 2009 fire at a pistachio processing warehouse, where rainwater reacted with aluminum phosphide fumigants to produce impure phosphine gas that autoignited. Compared to , phosphine exhibits greater explosivity, attributable to the weaker P-H (322 kJ/mol) versus the N-H bond (391 kJ/mol), which facilitates more facile bond breaking and initiation.

Handling precautions

Phosphine must be stored in seamless steel cylinders designed for high-pressure gases, often stabilized with inert diluents such as or to prevent spontaneous decomposition and ignition. These cylinders are classified under UN 1055 as a Division 2.3 toxic gas with a subsidiary hazard of Division 2.1 flammable gas, requiring compliance with international transport regulations for hazardous materials. Storage areas should be well-ventilated, cool (below 52°C), and separated from oxidizers or ignition sources to minimize risks during transport and handling. Personal protective equipment (PPE) for handling phosphine includes (SCBA) with a full facepiece to protect against , as phosphine is not absorbed through intact but poses severe respiratory hazards. Gas-tight chemical protective suits are recommended for teams or high-exposure scenarios, with SCBA worn inside the suit for complete isolation. Continuous monitoring using phosphine-specific electrochemical gas detectors is essential to ensure exposure levels remain below occupational limits, typically alerting at 0.3 ppm. In the United States, phosphine is regulated as a restricted-use pesticide under the EPA's fumigant labeling requirements, mandating certified applicators, buffer zones, and posting of warning signs to protect workers and bystanders. In the European Union, phosphine falls under REACH registration and the Biocidal Products Regulation, with restrictions limiting emissions during fumigation to prevent environmental release and requiring closed systems for application. For response, immediate evacuation and ventilation of the affected area are critical to disperse the gas, followed by neutralization if feasible. Phosphine can be oxidized using a solution of (household ), as shown in the reaction: PH3+4NaOCl→H3PO4+4NaCl\text{PH}_3 + 4\text{NaOCl} \rightarrow \text{H}_3\text{PO}_4 + 4\text{NaCl} This converts phosphine to non-toxic and compounds, though excess should be used under controlled conditions to avoid secondary hazards.

Cultural depictions

In fiction

Phosphine has appeared in science fiction as a biological mechanism for dramatic effect. In Anne McCaffrey's series, genetically engineered dragons chew firestone, a phosphorus-rich , to produce phosphine gas in their stomachs, which they expel and ignite in air to breathe fire, enabling them to combat the airborne threat of Thread. The gas's toxicity has been exploited as a in modern media. In the television series (2009), chemistry teacher Walter White synthesizes phosphine by reacting red scraped from matchbooks with hot water, releasing the colorless, odorless gas to asphyxiate and kill two criminals trapped with him, underscoring its rapid and fatal effects even at low concentrations. Symbolically, phosphine represents industrial peril in contemporary eco-thrillers, where it symbolizes the hidden dangers of chemical and in narratives about environmental collapse.

In media and symbolism

The detection of phosphine in 's atmosphere in captured widespread attention in media for its potential as a indicating microbial life. The program The Sky at Night: Life beyond Venus, aired on November 8, , examined the scientific community's response to the discovery, noting phosphine's rarity in non-biological processes and its production by anaerobic microbes on , which fueled speculation about habitable conditions in Venus's clouds. This coverage, presented by hosts Chris Lintott and , underscored the debate over whether the gas signal truly pointed to extraterrestrial or alternative chemical origins. News outlets amplified astrobiological excitement in 2025 with reports on the proposed (Venus Explorer for Reduced Vapours in the Environment) mission, a low-cost probe designed to sample and map gases like and in Venus's upper atmosphere. Articles in EarthSky highlighted how could confirm or refute the 2020 findings, potentially revolutionizing the search for life by targeting the planet's temperate cloud layers. Similarly, IEEE Spectrum described the mission's role in addressing ongoing hype, emphasizing detections of these reduced gases as Earth-like signatures produced almost exclusively by in oxygen-poor environments. Coverage in stressed 's £43 million budget and focus on hydrogen-bearing molecules, positioning it as a pivotal step in resolving Venus's puzzle. Phosphine has also served as a in environmental discourse, representing the hazards of agrochemicals due to its use as a highly toxic fumigant in grain storage and . In , a 2023 regulatory reversal allowing continued phosphine application for grain exports—despite initial bans by the food safety authority—drew criticism from environmental advocates concerned about health risks and trade impacts on pest in . However, in August 2025, 's constitutional court blocked the reintroduction of phosphine alongside other controversial , highlighting ongoing debates over , where it embodies the tension between agricultural efficiency and ecological safety, as phosphine generates lethal gas upon reaction with moisture but poses risks of resistance in pests and accidental exposure. Educational media has portrayed phosphine since the to illustrate principles. Khan Academy's chemistry curriculum features videos on phosphine's properties, synthesis via of metal phosphides, and reactions, such as its spontaneous flammability in air, aimed at high school and college learners to build understanding of p-block elements.

References

  1. https://pubchem.ncbi.nlm.nih.gov/compound/Phosphine
  2. https://www.cdpr.ca.gov/wp-content/uploads/2024/10/phosphine.pdf
  3. https://webbook.nist.gov/cgi/cbook.cgi?ID=C7803512
  4. https://www.epa.gov/sites/default/files/2016-09/documents/phosphine.pdf
  5. https://wwwn.cdc.gov/TSP/MMG/MMGDetails.aspx?mmgid=1013&toxid=214
  6. https://www.cdc.gov/niosh/npg/npgd0505.html
  7. https://www.nature.com/articles/s41550-020-1174-4
  8. https://phys.org/news/2025-10-phosphine-brown-dwarf-atmosphere.html
  9. https://byjus.com/jee/hybridization-of-ph3/
  10. https://allen.in/jee/chemistry/hybridization-of-ph3
  11. https://vpl.astro.washington.edu/spectra/ph3.htm
  12. https://cccbdb.nist.gov/exp2x.asp?casno=7803512
  13. https://www.eiga.eu/uploads/documents/DOC162.pdf
  14. https://onlinelibrary.wiley.com/doi/10.1002/anie.202501656
  15. https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.1930.0108
  16. https://www.researchgate.net/publication/227299354_The_Chemistry_of_Phosphine
  17. https://pubs.rsc.org/en/content/articlelanding/1933/jr/jr9330000586
  18. https://organicchemistrydata.org/hansreich/resources/pka/pka_data/pka-compilation-williams.pdf
  19. https://pmc.ncbi.nlm.nih.gov/articles/PMC9501927/
  20. https://www.inchem.org/documents/ehc/ehc/ehc73.htm
  21. https://onlinelibrary.wiley.com/doi/pdf/10.1002/9780470132456.ch1
  22. https://pubs.acs.org/doi/pdf/10.1021/jo01037a050
  23. https://www.essentialchemicalindustry.org/chemicals/phosphorus.html
  24. https://pubs.acs.org/doi/10.1021/acscentsci.3c00056
  25. https://link.springer.com/article/10.1134/S0020168509120152
  26. https://uvm.technologypublisher.com/tech/Preparations_of_Primary_Phosphines
  27. https://www.syensqo.com/en/chemical-categories/phosphorus-specialties
  28. https://www.nippon-chem.co.jp/en/en_research_development/en_introduction/en_phosphine.html
  29. https://asiaiga.org/uploaded_docs/en_AIGA_051_20_Code_of_Practice_Phsophine.pdf
  30. https://www.nature.com/articles/srep08355
  31. https://www.pnas.org/doi/10.1073/pnas.2021689118
  32. https://www.sciencedirect.com/science/article/abs/pii/S0045653520324085
  33. https://www.sciencedirect.com/science/article/abs/pii/S0964830519307115
  34. https://pubmed.ncbi.nlm.nih.gov/10811253/
  35. https://www.sciencedirect.com/science/article/abs/pii/S1075996499901993
  36. https://www.mdpi.com/2073-4441/9/8/563
  37. https://www.nature.com/articles/s41612-020-00154-7
  38. https://pubmed.ncbi.nlm.nih.gov/10995315/
  39. https://pubs.acs.org/doi/10.1021/jf991221v
  40. https://ui.adsabs.harvard.edu/abs/1982Icar...49..416D/abstract
  41. https://adsabs.harvard.edu/full/1980ApJ...240..327L
  42. https://www.sciencedirect.com/science/article/abs/pii/S0019103509001328
  43. https://arxiv.org/abs/2409.12907
  44. https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2024.1451127/full
  45. https://www.science.org/doi/10.1126/science.adu0401
  46. https://arxiv.org/abs/2510.03916
  47. https://www.tandfonline.com/doi/abs/10.1080/01496398808075627
  48. https://www.chm.bris.ac.uk/motm/phosphine/phosphineh.htm
  49. https://royalsocietypublishing.org/doi/10.1098/rstl.1818.0019
  50. https://www.chemeurope.com/en/encyclopedia/Phosphine.html
  51. https://royalsocietypublishing.org/doi/10.1098/rstl.1857.0029
  52. https://pubs.aip.org/aip/jcp/article/31/2/449/1031593/Electron-Diffraction-Study-of-the-Structure-of
  53. https://www.nobelprize.org/uploads/2018/06/knowles-lecture.pdf
  54. https://www.researchgate.net/publication/322788804_Transforming_the_homogeneous_catalysis_fifty_years_of_Wilkinson%27s_catalyst_Transformando_la_catalisis_homogenea_cincuenta_anos_del_catalizador_de_Wilkinson
  55. https://adsabs.harvard.edu/full/1977ApJ...211..972L
  56. https://www.livescience.com/life-on-venus-pioneer-13.html
  57. https://arxiv.org/abs/2409.13438
  58. https://spectrum.ieee.org/life-on-venus-verve-mission
  59. https://dspace.mit.edu/bitstream/handle/1721.1/135598/ast.2020.2352.pdf
  60. https://www.liebertpub.com/doi/10.1089/ast.2020.2352
  61. https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2024.1372057/full
  62. https://www.liebertpub.com/doi/10.1089/ast.2018.1954
  63. https://www.forbes.com/sites/jamiecartereurope/2023/07/06/phosphine-confirmed-deep-within-venus-atmosphere-a-possible-sign-of-life/
  64. https://www.supercluster.com/editorial/more-signs-of-life-revealed-on-venus
  65. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL101055
  66. https://newsroom.usra.edu/no-phosphine-on-venus--according-to-observations-from-sofia/
  67. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2023GL103539
  68. https://www.unsw.edu.au/newsroom/news/2025/10/mysterious-molecule-found-on-brown-dwarf-casts-further-doubt-on-potential-signs-of-life-on-venus
  69. https://www.forbes.com/sites/jamiecartereurope/2025/07/10/new-uk-mission-could-prove-signs-of-alien-life-on-venus/
  70. https://www.esa.int/Science_Exploration/Space_Science/Envision/ESA_selects_revolutionary_Venus_mission_Envision
  71. https://www.eaobservatory.org/jcmt/science/large-programs/jcmt-venus-monitoring-phosphine-and-other-molecules-in-venuss-atmosphere/
  72. https://www.organic-chemistry.org/namedreactions/arbuzov-reaction.shtm
  73. https://www.researchgate.net/publication/322137260_Synthesis_of_Phosphonates_via_Michaelis-Arbuzov_Reaction
  74. https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Organic_Chemistry_%28Morsch_et_al.%29/19%253A_Aldehydes_and_Ketones-_Nucleophilic_Addition_Reactions/19.11%253A_Nucleophilic_Addition_of_Phosphorus_Ylides_-_The_Wittig_Reaction
  75. https://www.masterorganicchemistry.com/2018/02/06/wittig-reaction/
  76. https://www.mdpi.com/2073-4344/7/9/267
  77. https://pubs.rsc.org/en/content/articlelanding/2025/qo/d4qo02079k
  78. https://www.nature.com/articles/s41467-024-46892-7
  79. https://pubs.aip.org/aip/jap/article-pdf/59/12/4032/18605350/4032_1_online.pdf
  80. https://www.syensqo.com/en/brands/cypure
  81. https://www.sphericalinsights.com/reports/phosphine-gas-ph3-market
  82. https://patents.google.com/patent/US5120676A/en
  83. https://www.fao.org/4/x5042e/x5042e0n.htm
  84. https://pmc.ncbi.nlm.nih.gov/articles/PMC3135219/
  85. https://www.degeschamerica.com/products/fumigants/
  86. https://extension.okstate.edu/fact-sheets/safety-education-is-critical-for-grain-fumigators.html
  87. https://www.sciencedirect.com/science/article/abs/pii/S0022474X11000695
  88. https://www.mordorintelligence.com/industry-reports/grain-fumigants-market
  89. https://www.mdpi.com/2075-4450/15/10/802
  90. https://osha.oregon.gov/OSHAPubs/factsheets/fs54.pdf
  91. https://npic.orst.edu/mcapro/phosphine.html
  92. https://nj.gov/health/eoh/rtkweb/documents/fs/1514.pdf
  93. https://pmc.ncbi.nlm.nih.gov/articles/PMC6309866/
  94. https://pmc.ncbi.nlm.nih.gov/articles/PMC4975009/
  95. https://www.researchgate.net/publication/303510305_Phosphine_toxicity_a_story_of_disrupted_mitochondrial_metabolism_The_toxicology_of_phosphine_poisoning
  96. https://www.osha.gov/chemicaldata/667
  97. https://www.gov.uk/government/publications/phosphine-properties-incident-management-and-toxicology/phosphine-toxicological-overview
  98. https://maritimecyprus.com/2024/03/19/bahamas-marine-investigation-report-fumigation-poisoning-fatality-on-m-v-magic-striker-on-21-dec-2021/
  99. https://research.uiowa.edu/news/2025/01/meet-phosphine-gas-commonly-used-industrial-fumigation-can-damage-your-lungs-heart-and
  100. https://www.airgas.com/msds/001070.pdf
  101. https://cameochemicals.noaa.gov/chemical/1322
  102. https://amp.generalair.com/MsdsDocs/PA46432S.pdf
  103. https://www.worksafe.qld.gov.au/safety-and-prevention/hazards/hazardous-exposures/phosphine-gas
  104. https://pubmed.ncbi.nlm.nih.gov/23540306/
  105. https://www.unece.org/fileadmin/DAM/trans/danger/publi/unrec/rev19/Rev19e_Vol_I.pdf
  106. https://apps.mnc.umn.edu/pub/msds/phosphine.pdf
  107. https://www.draeger.com/en-us_us/Substances/354
  108. https://www.indsci.com/en/industrial-scientific-gas-types-phosphine-ph3-0
  109. https://www.epa.gov/soil-fumigants/regulatory-status-fumigants
  110. https://www.echa.europa.eu/registration-dossier/-/registered-dossier/18616/9
  111. https://worldbuilding.stackexchange.com/questions/162480/recreating-dragon-fire
  112. https://edu.rsc.org/analysis/breaking-bad-poisoning-gangsters-with-phosphine-gas/3007373.article
  113. https://www.bbc.co.uk/programmes/m000p9s7
  114. https://earthsky.org/space/life-on-venus-verve-envision-esa-astrobiology/
  115. https://www.universetoday.com/articles/uk-is-considering-a-mission-to-venus-to-search-for-life
  116. https://www.rfi.fr/en/france/20230425-phosphine-metolachlor-pesticide
  117. https://www.politico.eu/article/frances-top-court-blocks-comeback-of-controversial-insecticide/
  118. https://www.khanacademy.org/science/ka-chemistry-grade-12/xde7d06e720e32944:the-p-block-elements
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