Monophosphine

Structural formula
General
Surname	Monophosphine
other names	Phosphine Phosphine Phosphane
Molecular formula	PH 3
Brief description	flammable, toxic, colorless and odorless gas. Garlic and rotten fish smell due to impurities
External identifiers / databases
CAS number 7803-51-2 EC number 232-260-8 ECHA InfoCard 100,029,328 PubChem 24404 ChemSpider 22814 Wikidata Q207877
properties
Molar mass	34,00 g · mol -1
Physical state	gaseous
density	1.53 kg m −3 (0 ° C)
Melting point	−133.8 ° C
boiling point	−87.8 ° C
Vapor pressure	3.49 M Pa (20 ° C)
solubility	very heavy in water (330 mg l −1 at 20 ° C)
Refractive index	1.224 (16.85 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 220-280-330-314-400 P: 210-260-273-280-303 + 361 + 353-304 + 340-305 + 351 + 338-315-377-381-403-405
MAK	DFG : 0.14 mg m −3 Switzerland: 0.1 ml m −3 or 0.15 mg m −3
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Monophosphane , colloquially imprecisely referred to as hydrogen phosphide or outdated as phosphine , belongs to the group of phosphanes . Monophosphine is a chemical compound of the element phosphorus with the empirical formula PH ₃ .

Monophosphane is a flammable , extremely poisonous gas that is odorless in its pure state . Pure monophosphine is only self-igniting at 150 ° C. Due to the presence of diphosphane P ₂ H ₄ , commercially available gas prepared in the laboratory burns even at room temperature when air is supplied; the diphosphine and other phosphines give this monophosphine, which is usually not quite pure, a strong garlic odor.

As a mutagenic clastogen , it can act as a poison by causing chromosomal aberrations and thus having a carcinogenic effect.

It was first presented by the Lavoisier student Philippe Gengembre in 1789, in the liquid self-igniting form by Paul Thénard in 1845, who also found the solid form, and the first direct analysis was carried out by Ludwig Gattermann in 1890.

The detection of monophosphine in the atmosphere has been suggested as a possible indication of life on earth-like planets , as it can be detected spectroscopically and is only produced biologically or artificially on earth. On September 14, 2020, the detection of monophosphane in the atmosphere of Venus was announced in a publication in Nature Astronomy , whereby a mechanism for the formation of the gas in the Venusian atmosphere is so far unknown. In the atmosphere of the gas planets Jupiter and Saturn , monophosphane has been known since the 1970s and is probably formed here under high pressure in the deeper, hot regions.

Extraction and presentation

There are numerous ways to represent monophosphine. For example, white phosphorus (P ₄ ) disproportionates in an alkaline medium to phosphine and phosphinic acid , which at higher temperatures disproportionates to monophosphine and phosphonic acid, which in turn disproportionates to phosphoric acid and monophosphine:

${\displaystyle \mathrm {2\ P_{4}+12\ H_{2}O\longrightarrow } }$ ${\displaystyle \mathrm {2\ PH_{3}+6\ H_{3}PO_{2}\longrightarrow } }$ ${\displaystyle \mathrm {4\ PH_{3}+4\ H_{3}PO_{3}\longrightarrow } }$ ${\displaystyle \mathrm {5\ PH_{3}+3\ H_{3}PO_{4}} }$

This method is carried out technically in an autoclave at 250 ° C.

Analogous to the production of ammonia ( Haber-Bosch process ), a synthesis from the elements can also take place:

${\displaystyle \mathrm {P_{4}+6\ H_{2}\longrightarrow 4\ PH_{3}} }$

Monophosphine is also formed in the acid hydrolysis of salt-like phosphides and phosphonium salts, as well as in the hydridolysis of phosphorus halides such. B. phosphorus trichloride with lithium aluminum hydride in ether.

In the laboratory, monophosphine is produced in an almost quantitative yield by thermal decomposition of crystalline phosphonic acid between 200 and 350 ° C

${\displaystyle {\ce {4 H3PO3 ->[T][] 3 H3PO4 + PH3}}}$

or obtained by reacting aluminum phosphide with concentrated sulfuric acid :

${\displaystyle {\ce {2 AlP + 3 H2SO4 -> 2 PH3 + Al2(SO4)3}}}$

properties

Physical Properties

Monophosphane is hardly soluble in water, the aqueous solution reacts neutrally.

The molecule has a trigonal-pyramidal structure. The angle between the individual hydrogen atoms is 93.5 °. The distance between the phosphorus and hydrogen atoms is 1.419 Å .

Geometry of monophosphane

Critical temperature	51.9 ° C
Critical pressure	65.3 bar
Gibbs energy	13 kJ / mol
Standard entropy	210 J / (mol K)
Heat capacity	37 J / (mol K)
Enthalpy of evaporation	1 kJ / mol
Electric dipole moment	1.9 x 10 -30 C-m

Chemical properties

Monophosphine is a weak base ( pK _b ~ 27). It reacts with hydrohalic acids to form unstable salts, the so-called phosphonium salts. At high temperatures it decomposes into the elements hydrogen and phosphorus.

With strong bases such as sodium amide or butyllithium , the hydrogen atoms can be replaced by alkali metals . The so-called phosphides can be synthesized by substituting all hydrogen atoms .

The standard reduction potential is −0.063 V in an acidic environment and −0.89 V in a basic environment.

At 150 ° C, pure monophosphine ignites in air and is oxidized to phosphoric acid:

${\displaystyle \mathrm {PH_{3}+2\ O_{2}\longrightarrow H_{3}PO_{4}+1270\ kJ} }$

In the presence of traces of 0.2% diphosphine , monophosphine immediately ignites spontaneously in the presence of air.

use

Monophosphane is used for pest control , especially for mice and insect control in grain silos and storage of plant products. The fumigation can be carried out by specialists directly with monophosphane gas. Instead, solid preparations (e.g. with the active ingredient aluminum phosphide AlP or calcium phosphide Ca ₃ P ₂ ) are often designed, which react with the humidity in the air and thus release the monophosphine gas.

It is also used in the manufacture of light emitting diodes for doping with phosphorus. It is also used for the synthesis of various organic compounds.

Attempts have also been made to fertilize phosphorus using monophosphane.

safety instructions

→ Main article : Phosphorus poisoning

Monophosphine is a very strong nerve and metabolic poison that is highly effective not only in mammals but also in insects even at low concentrations. In humans, it causes a drop in blood pressure, vomiting, pulmonary edema and coma . In addition, traces of diphosphine in the air make monophosphane self-igniting, so strict safety precautions are necessary when handling.

proof

The easiest way to detect monophosphane is with so-called test tubes or corresponding sensors. In addition, the smell of phosphine (more precisely, the smell of the contained impurities) is perceptible from a concentration of 2 ppm .

literature

• Product information from AIR LIQUIDE
• Entry on phosphanes. In: Römpp Online . Georg Thieme Verlag, accessed on July 26, 2013.
• Robert C. Weast (Ed.): CRC Handbook of Chemistry and Physics. 60th edition. CRC Press, Boca Raton FL 1979, ISBN 0-8493-0460-8 .
• AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 .
• GH Aylward; TJV Findlay: Chemistry data collection in SI units. 3rd, expanded and revised edition. Wiley-VCH, Weinheim u. a. 1999, ISBN 3-527-29468-6 .

Individual evidence

1. ↑ ^{a b c d e f g h i j k} Entry on hydrogen phosphide in the GESTIS substance database of the IFA , accessed on July 23, 2016(JavaScript required) .
2. ↑ PG Sennikov, VE Shkrunin, DA Raldugin, KG Tokhadze: Weak Hydrogen Bonding in Ethanol and Water Solutions of Liquid Volatile Inorganic Hydrides of Group IV-VI Elements (SiH ₄ , GeH ₄ , PH ₃ , AsH ₃ , H ₂ S, and H ₂ Se). 1. IR Spectroscopy of H Bonding in Ethanol Solutions in Hydrides . In: The Journal of Physical Chemistry . tape 100 , no. January 16 , 1996, p. 6415-6420 , doi : 10.1021 / jp953245k .
3. ↑ Entry on phosphines in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
4. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 7803-51-2 or monophosphane ), accessed on November 2, 2015.
5. ↑ Oyeronke A. Odunola, Aliyu Muhammad, Ahsana D. Farooq, Kourosh Dalvandi, Huma Rasheed, Muhammad I. Choudhary, Ochuko L. Erukainure: Comparative assessment of redox-sensitive biomarkers due to acacia honey and sodium arsenite administration in vivo. In: Mediterranean Journal of Nutrition and Metabolism 6, No. 2, 2013, pp. 119-126, doi: 10.1007 / s12349-013-0127-1 .
6. ↑ Gengembre, About a new air, which is obtained through the action of lye salts on Kunckel's phosphorus, Crells Chemische Annalen, Volume 11, 1789, pp. 450–457
7. ^ Thénard, Mémoire sur les combinaisons du phosphore avec l'hydrogène, Ann. Chim., Row 3, Volume 14, 1845, pp. 5-50
8. ^ Gattermann, W. Haussknecht, Investigations on the self-igniting hydrogen phosphide, reports of the German Chemical Society, Volume 23, 1890, pp. 1174–1190
9. ↑ Clara Sousa-Silva, Sara Seager, Sukrit Ranjan, Janusz Jurand Petkowski, Zhuchang Zhan, Renyu Hu, and William Bains: Phosphine as a Biosignature Gas in Exoplanet Atmospheres . In: Astrobiology . tape 20 , no. 2 , 2020, doi : 10.1089 / ast.2018.1954 . S. a. Preprint (PDF, 4.56 MB) (accessed September 15, 2020).
10. ↑ Greaves, JS, Richards, AMS, Bains, W. et al .: Phosphine gas in the cloud decks of Venus . In: Nature Astronomy . 2020, doi : 10.1038 / s41550-020-1174-4 .
11. ^ Jack A. Kaye, Darrell F. Strobel: Phosphine Photochemistry in the Atmosphere of Saturn . In: Icarus . tape 59 , 1984, pp. 314--335 , doi : 10.1016 / 0019-1035 (84) 90105-2 .
12. ^ Sudarshan D. Gokhale and William L. Jolly: Phosphine . In: S. Young Tyree, Jr. (Ed.): Inorganic Syntheses . tape 9 . McGraw-Hill Book Company, Inc., 1967, p. 56-58 (English).
13. ^ Robert C. Marriott et al .: Phosphine . In: Aaron Wold and John K. Ruff (Eds.): Inorganic Syntheses . tape 14 . McGraw-Hill Book Company, Inc., 1973, ISBN   07-071320-0  ( defective ) , p. 1-4 (English).
14. ↑ M. Binnewies et al .: General and Inorganic Chemistry . 2nd Edition. Spectrum, 2010, ISBN 3-8274-2533-6 , pp. 511 .
15. ↑ PG Urban, MJ Pitt (Ed.): Bretherick's Handbook of Reactive Chemical Hazards. 6th edition. Butterworths-Heinemann, Oxford a. a., ISBN 0-7506-3605-X .