Phosphine

Phosphine
Names
IUPAC name
Phosphane
Other names
Phosphamine
Phosphorus trihydride
Phosphorated hydrogen
Identifiers
CAS Number
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.029.328
Edit this at Wikidata
EC Number
  • 232-260-8
Gmelin Reference
 287
PubChem CID
RTECS number
  • SY7525000
UNII
UN number 2199
InChI
  • InChI=1S/H3P/h1H3 checkY
    Key: XYFCBTPGUUZFHI-UHFFFAOYSA-N checkY
  • InChI=1/H3P/h1H3
    Key: XYFCBTPGUUZFHI-UHFFFAOYAP
SMILES
  • P
Properties
Chemical formula
 PH3
Molar mass 33.99758 g/mol
Appearance Colourless gas
Odor fish-like or garlic-like[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)
Solubility in water
 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 (chemical formula PH+
4)
Refractive index (nD)
 2.144
Viscosity 1.1×10−5 Pa⋅s
Structure
Molecular shape
 Trigonal pyramidal
Dipole moment
 0.58 D
Thermochemistry
Heat capacity (C)
 37 J/mol⋅K
Std molar
entropy (So298)
 210 J/mol⋅K[2]
Std enthalpy of
formation (ΔfH⦵298)
 5 kJ/mol[2]
Gibbs free energy (ΔfG˚)
 13 kJ/mol
Hazards
GHS labelling:
Pictograms
NFPA 704 (fire diamond)
4
4
2
Flash point Flammable gas
Autoignition
temperature
 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
  • Ammonia
  • Arsine
  • Stibine
  • Bismuthine
Related compounds
  • Trimethylphosphine
  • Triphenylphosphine
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 ?)
Infobox references

Phosphine (IUPAC name: phosphane) is a colorless, flammable, very toxic gas 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.

Phosphine is also the general name given to the class of organophosphorus compounds in which one or all of hydrogen atoms in PH3 been replaced with organic derivative, having a general formula PH3−nRn. Organophosphines are important in catalysts.

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).[4][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.[5] 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][6] The gas PH3 was named "phosphine" by 1865 (or earlier).[7]

Structure and properties

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 bonding between phosphorus and hydrogen in this molecule. For this reason, the lone pair on phosphorus may be regarded as predominantly formed by the 3s orbital of phosphorus. The upfield chemical shift of the phosphorus atom in the 31P NMR spectrum 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),[8] as well as an ability to form only weak hydrogen bonds.[9]

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 burns producing a dense white cloud of phosphoric acid:

PH3 + 2 O2 → H3PO4

Preparation and occurrence

Phosphine may be prepared in a variety of ways.[10] 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

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. It can also be made (as described above) by the hydrolysis of a metal phosphide, such as aluminium phosphide or calcium phosphide. Pure samples of phosphine, free from P2H4, may be prepared using the action of potassium hydroxide on phosphonium iodide (PH4I).

Laboratory routes

It is prepared in the laboratory by disproportionation of phosphorous acid[11]

4 H3PO3 → PH3 + 3 H3PO4

Phosphine evolution occurs at around 200 °C. Alternative methods involve the hydrolysis of aluminium phosphide, calcium phosphide, and tris(trimethylsilyl)phosphine.

Occurrence

Phosphine is a constituent of the Earth's atmosphere at very low and highly variable concentrations.[12] 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.[13]

It is also found in Jupiter's atmosphere.[14]

Possible extraterrestrial biosignature

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.[15][16][17] Later re-analysis of this work showed interpolation errors has been made, re-analysis of data with the fixed algorithm either do not result in the detection of phosphine[18][19] or detect it with a much lower concentration of 1 ppb.[20]

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 PH3 adds of Michael acceptors such as acrylonitrile:[21]

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 (R is Me, alkyl, etc.)

Microelectronics

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.[22]

Fumigant

For farm use, pellets of aluminium phosphide, calcium phosphide, or zinc phosphide release phosphine upon contact with atmospheric water or rodents' stomach acid. These pellets also contain agents to reduce the potential for ignition or explosion of the released phosphine. A more recent 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.

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

Toxicity and safety

Deaths have resulted from accidental exposure to fumigation materials containing aluminium phosphide or phosphine.[24][25][26][27] It can be absorbed either by inhalation or transdermally.[24] As a respiratory poison, it affects the transport of oxygen or interferes with the utilization of oxygen by various cells in the body.[26] Exposure results in pulmonary edema (the lungs fill with fluid).[27] Phosphine gas is heavier than air so stays nearer the floor.[28]

Phosphine appears to be mainly a redox toxin, causing cell damage by inducing oxidative stress and mitochondrial dysfunction.[29] Resistance in insects is caused by a mutation in a mitochondrial metabolic gene.[23]

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.

Phosphine can be absorbed into the body by inhalation. Direct contact with phosphine liquid – although unlikely to occur – may cause frostbite, like other cryogenic liquids. The main target organ of phosphine gas is the respiratory tract.[30] 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.[31][32] 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.[33]

See also

  • Diphosphane, H2PPH2, simplified to H4P2
  • Diphosphene, HP=PH

Notes

  1. ↑ For further information about the early history of phosphine, see:
    • The Encyclopædia Britannica (1911 edition), vol. 21, p. 480: Phosphorus: Phosphine. Archived 4 November 2015 at the Wayback Machine
    • Thomas Thomson, A System of Chemistry, 6th ed. (London, England: Baldwin, Cradock, and Joy, 1820), vol. 1, p. 272. Archived 4 November 2015 at the Wayback Machine
  2. ↑ Note:
    • On p. 222 Archived 24 April 2017 at the Wayback Machine of his Traité élémentaire de chimie, vol. 1, (Paris, France: Cuchet, 1789), Lavoisier calls the compound of phosphorus and hydrogen "phosphure d'hydrogène" (hydrogen phosphide). However, on p. 216 Archived 24 April 2017 at the Wayback Machine, he calls the compound of hydrogen and phosphorus "Combinaison inconnue." (unknown combination), yet in a footnote, he says about the reactions of hydrogen with sulfur and with phosphorus: "Ces combinaisons ont lieu dans l'état de gaz & il en résulte du gaz hydrogène sulfurisé & phosphorisé." (These combinations occur in the gaseous state, and there results from them sulfurized and phosphorized hydrogen gas.)
    • In Robert Kerr's 1790 English translation of Lavoisier's Traité élémentaire de chimie ... — namely, Lavoisier with Robert Kerr, trans., Elements of Chemistry ... (Edinburgh, Scotland: William Creech, 1790) — Kerr translates Lavoisier's "phosphure d'hydrogène" as "phosphuret of hydrogen" (p. 204), and whereas Lavoisier — on p. 216 of his Traité élémentaire de chimie ... — gave no name to the combination of hydrogen and phosphorus, Kerr calls it "hydruret of phosphorus, or phosphuret of hydrogen" (p. 198). Lavoisier's note about this compound — "Combinaison inconnue." — is translated: "Hitherto unknown." Lavoisier's footnote is translated as: "These combinations take place in the state of gas, and form, respectively, sulphurated and phosphorated oxygen gas." The word "oxygen" in the translation is an error because the original text clearly reads "hydrogène" (hydrogen). (The error was corrected in subsequent editions.)
  3. ↑ 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).

References

  1. 1 2 3 4 5 6 NIOSH Pocket Guide to Chemical Hazards. "#0505". National Institute for Occupational Safety and Health (NIOSH).
  2. 1 2 Zumdahl, Steven S. (2009). Chemical Principles (6th ed.). Houghton Mifflin. p. A22. ISBN 978-0-618-94690-7.
  3. 1 2 "Phosphine". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. ↑ Gengembre (1783) "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.
  5. ↑ Paul Thénard (1844) "Mémoire sur les combinaisons du phosphore avec l'hydrogène" Archived 15 October 2015 at the Wayback Machine (Memoir on the compounds of phosphorus with hydrogen), Comptes rendus, 18 : 652–655.
  6. ↑ A.W. Hofmann; Auguste Cahours (1857). "Researches on the phosphorus bases". Proceedings of the Royal Society of London (8): 523–527. Archived from the original on 10 February 2022. Retrieved 19 November 2020. (From page 524:) The bases Me3P and E3P, the products of this reaction, which we propose to call respectively trimethylphosphine and triethylphosphine, ...
  7. ↑ William Odling, A Course of Practical Chemistry Arranged for the Use of Medical Students, 2nd ed. (London, England: Longmans, Green, and Co., 1865), pp. 227, 230.
  8. ↑ Streitwieser, Andrew; Heathcock, Clayton H.; Kosower, Edward M. (2017). Introduction to Organic Chemistry. New Delhi: Medtech (Scientific International, reprint of revised 4th edition, Macmillan, 1998). p. 828. ISBN 9789385998898.
  9. ↑ Sennikov, P. G. (1994). "Weak H-Bonding by Second-Row (PH3, H2S) and Third-Row (AsH3, H2Se) Hydrides". Journal of Physical Chemistry. 98 (19): 4973–4981. doi:10.1021/j100070a006.
  10. ↑ Toy, A. D. F. (1973). The Chemistry of Phosphorus. Oxford, UK: Pergamon Press.
  11. ↑ Gokhale, S. D.; Jolly, W. L., "Phosphine", Inorganic Syntheses 1967, volume 9, pp. 56–58. doi:10.1002/9780470132401.ch17
  12. ↑ Gassmann, G.; van Beusekom, J. E. E.; Glindemann, D. (1996). "Offshore atmospheric phosphine". Naturwissenschaften. 83 (3): 129–131. Bibcode:1996NW.....83..129G. doi:10.1007/BF01142178. S2CID 39778453.
  13. ↑ Roels, J.; Verstraete, W. (2001). "Biological formation of volatile phosphorus compounds, a review paper". Bioresource Technology. 79 (3): 243–250. doi:10.1016/S0960-8524(01)00032-3. PMID 11499578.
  14. ↑ Kaplan, Sarah (11 July 2016). "The first water clouds are found outside our solar system — around a failed star". The Washington Post. Archived from the original on 15 September 2020. Retrieved 14 September 2020.
  15. ↑ Sousa-Silva, Clara; Seager, Sara; Ranjan, Sukrit; Petkowski, Janusz Jurand; Zhan, Zhuchang; Hu, Renyu; Bains, William (11 October 2019). "Phosphine as a Biosignature Gas in Exoplanet Atmospheres". Astrobiology (published February 2020). 20 (2): 235–268. arXiv:1910.05224. Bibcode:2020AsBio..20..235S. doi:10.1089/ast.2018.1954. PMID 31755740. S2CID 204401807.
  16. ↑ Chu, Jennifer (18 December 2019). "A sign that aliens could stink". MIT News. Archived from the original on 18 February 2021. Retrieved 14 September 2020.
  17. ↑ "Phosphine Could Signal Existence of Alien Anaerobic Life on Rocky Planets". Sci-News. 26 December 2019. Archived from the original on 14 September 2020. Retrieved 15 September 2020.
  18. ↑ Snellen, I. A. G.; Guzman-Ramirez, L.; Hogerheijde, M. R.; Hygate, A. P. S.; van der Tak, F. F. S. (2020), "Re-analysis of the 267-GHz ALMA observations of Venus No statistically significant detection of phosphine", Astronomy and Astrophysics, 644: L2, arXiv:2010.09761, Bibcode:2020A&A...644L...2S, doi:10.1051/0004-6361/202039717, S2CID 224803085
  19. ↑ Thompson, M. A. (2021), "The statistical reliability of 267 GHz JCMT observations of Venus: No significant evidence for phosphine absorption", Monthly Notices of the Royal Astronomical Society: Letters, 501 (1): L18–L22, arXiv:2010.15188, Bibcode:2021MNRAS.501L..18T, doi:10.1093/mnrasl/slaa187, S2CID 225103303
  20. ↑ Greaves, Jane S.; Richards, Anita M. S.; Bains, William; Rimmer, Paul B.; Clements, David L.; Seager, Sara; Petkowski, Janusz J.; Sousa-Silva, Clara; Ranjan, Sukrit; Fraser, Helen J. (2021), "Reply to: No evidence of phosphine in the atmosphere of Venus from independent analyses", Nature Astronomy, 5 (7): 636–639, arXiv:2011.08176, Bibcode:2021NatAs...5..636G, doi:10.1038/s41550-021-01424-x, S2CID 233296859
  21. ↑ Trofimov, Boris A.; Arbuzova, Svetlana N.; Gusarova, Nina K. (1999). "Phosphine in the Synthesis of Organophosphorus Compounds". Russian Chemical Reviews. 68 (3): 215–227. Bibcode:1999RuCRv..68..215T. doi:10.1070/RC1999v068n03ABEH000464.
  22. ↑ Bettermann, G.; Krause, W.; Riess, G.; Hofmann, T. (2002). "Phosphorus Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_527.
  23. 1 2 Schlipalius, D. I.; Valmas, N.; Tuck, A. G.; Jagadeesan, R.; Ma, L.; Kaur, R.; et al. (2012). "A Core Metabolic Enzyme Mediates Resistance to Phosphine Gas". Science. 338 (6108): 807–810. Bibcode:2012Sci...338..807S. doi:10.1126/science.1224951. PMID 23139334. S2CID 10390339.
  24. 1 2 Ido Efrati; Nir Hasson (22 January 2014). "Two toddlers die after Jerusalem home sprayed for pests". Haaretz. Archived from the original on 23 January 2014. Retrieved 23 January 2014.
  25. ↑ "La familia de Alcalá de Guadaíra murió tras inhalar fosfina de unos tapones". RTVE.es (in Spanish). Radio y Televisión Española. EFE. 3 February 2014. Archived from the original on 2 March 2014. Retrieved 23 July 2014.
  26. 1 2 Julia Sisler (13 March 2014). "Deaths of Quebec women in Thailand may have been caused by pesticide". CBC News. Archived from the original on 4 April 2017. Retrieved 3 April 2017.
  27. 1 2 Amy B Wang (3 January 2017). "4 children killed after pesticide released toxic gas underneath their home, police say". Washington Post. Archived from the original on 25 June 2018. Retrieved 6 January 2017.
  28. ↑ "Pesticide blamed in 8-month-old's death in Fort McMurray". CBC News. 23 February 2015. Archived from the original on 24 February 2015. Retrieved 23 February 2015.
  29. ↑ Nath, NS; Bhattacharya, I; Tuck, AG; Schlipalius, DI; Ebert, PR (2011). "Mechanisms of phosphine toxicity". Journal of Toxicology. 2011: 494168. doi:10.1155/2011/494168. PMC 3135219. PMID 21776261.
  30. ↑ "NIOSH Emergency Response Card". CDC. Archived from the original on 2 October 2017. Retrieved 6 April 2010.
  31. ↑ "NIOSH pocket guide". CDC. 3 February 2009. Archived from the original on 11 May 2017. Retrieved 6 April 2010.
  32. ↑ "WHO – Data Sheets on Pesticides – No. 46: Phosphine". Inchem.org. Archived from the original on 18 February 2010. Retrieved 6 April 2010.
  33. ↑ NIOSH alert: preventing phosphine poisoning and explosions during fumigation (Report). CDC. 1 September 1999. doi:10.26616/nioshpub99126. Archived from the original on 19 June 2017. Retrieved 6 April 2010.

Further reading

  • Fluck, E. (1973). "The Chemistry of Phosphine". Topics in Current Chemistry. Fortschritte der Chemischen Forschung. 35: 1–64. doi:10.1007/BFb0051358. ISBN 3-540-06080-4.
  • World Health Organisation (1988). Phosphine and Selected Metal Phosphides. Environmental Health Criteria. Vol. 73. Geneva: Joint sponsorship of UNEP, ILO and WHO.
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