Arsine

Not to be confused with arcsine or ursine.

Arsine

Ball-and-stick model of arsine Spacefill model of arsine   Arsenic, As   Hydrogen, H
Names
IUPAC names Arsenic trihydride Arsane Trihydridoarsenic
Other names Arseniuretted hydrogen, Arsenous hydride, Hydrogen arsenide Arsenic hydride
Identifiers
CAS Number	7784-42-1^Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:47217^Y
ChEMBL	ChEMBL1231052
ChemSpider	22408^Y
ECHA InfoCard	100.029.151
EC Number	232-066-3
Gmelin Reference	599
KEGG	C06269
PubChem CID	23969
RTECS number	CG6475000
UNII	V1I29R0RJQ^Y
UN number	2188
CompTox Dashboard (EPA)	DTXSID3023760
InChI InChI=1S/AsH3/h1H3^Y Key: RBFQJDQYXXHULB-UHFFFAOYSA-N^Y InChI=1/AsH3/h1H3 Key: RBFQJDQYXXHULB-UHFFFAOYAH
SMILES [AsH3]
Properties
Chemical formula	AsH3
Molar mass	77.9454 g/mol
Appearance	Colourless gas
Odor	Faint, garlic-like
Density	4.93 g/L, gas; 1.640 g/mL (−64 °C)
Melting point	−111.2 °C (−168.2 °F; 162.0 K)
Boiling point	−62.5 °C (−80.5 °F; 210.7 K)
Solubility in water	0.2 g/100 mL (20 °C)[1] 0.07 g/100 mL (25 °C)
Solubility	soluble in chloroform, benzene
Vapor pressure	14.9 atm[1]
Conjugate acid	Arsonium
Structure
Molecular shape	Trigonal pyramidal
Dipole moment	0.20 D
Thermochemistry
Std molar entropy (S^⦵298)	223 J⋅K^−1⋅mol^−1
Std enthalpy of formation (ΔfH^⦵298)	+66.4 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Extremely toxic, explosive, flammable, potential occupational carcinogen[1]
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H220, H330, H373, H410
Precautionary statements	P210, P260, P271, P273, P284, P304+P340, P310, P314, P320, P377, P381, P391, P403, P403+P233, P405, P501
NFPA 704 (fire diamond)	4 4 2
Flash point	−62 °C (−80 °F; 211 K)
Explosive limits	5.1–78%[1]
Lethal dose or concentration (LD, LC):
LD50 (median dose)	2.5 mg/kg (intravenous)[2]
LC50 (median concentration)	120 ppm (rat, 10 min) 77 ppm (mouse, 10 min) 201 ppm (rabbit, 10 min) 108 ppm (dog, 10 min)[3]
LCLo (lowest published)	250 ppm (human, 30 min) 300 ppm (human, 5 min) 25 ppm (human, 30 min)[3]
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.05 ppm (0.2 mg/m^3)[1]
REL (Recommended)	C 0.002 mg/m^3 [15-minute][1]
IDLH (Immediate danger)	3 ppm[1]
Related compounds
Related hydrides	Ammonia; phosphine; stibine; bismuthine
Supplementary data page
Arsine (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references

Arsine (IUPAC name: arsane) is an inorganic compound with the formula AsH₃. This flammable, pyrophoric, and highly toxic pnictogen hydride gas is one of the simplest compounds of arsenic.^[4] Despite its lethality, it finds some applications in the semiconductor industry and for the synthesis of organoarsenic compounds. The term arsine is commonly used to describe a class of organoarsenic compounds of the formula AsH_3−xR_x, where R = aryl or alkyl. For example, As(C₆H₅)₃, called triphenylarsine, is referred to as "an arsine".

General properties

In its standard state arsine is a colorless, denser-than-air gas that is slightly soluble in water (2% at 20 °C)^[1] and in many organic solvents as well.^{[citation needed]} Arsine itself is odorless,^[5] but it oxidizes in air and this creates a slight garlic or fish-like scent when the compound is present above 0.5 ppm.^[6] This compound is kinetically stable: at room temperature it decomposes only slowly. At temperatures of ca. 230 °C, decomposition to arsenic and hydrogen is sufficiently rapid to be the basis of the Marsh test for arsenic presence. Similar to stibine, the decomposition of arsine is autocatalytic, as the arsenic freed during the reaction acts as a catalyst for the same reaction.^[7] Several other factors, such as humidity, presence of light and certain catalysts (namely alumina) facilitate the rate of decomposition.^[8]

AsH₃ is a trigonal pyramidal molecule with H–As–H angles of 91.8° and three equivalent As–H bonds, each of 1.519 Å length.^[9]

Discovery and synthesis

AsH₃ is generally prepared by the reaction of As³⁺ sources with H⁻ equivalents.^[10]

4 AsCl₃ + 3 NaBH₄ → 4 AsH₃ + 3 NaCl + 3 BCl₃

As reported in 1775, Carl Scheele reduced arsenic(III) oxide with zinc in the presence of acid.^[11] This reaction is a prelude to the Marsh test.

Alternatively, sources of As³⁻ react with protonic reagents to also produce this gas. Zinc arsenide and sodium arsenide are suitable precursors:^[12]

Zn₃As₂ + 6 H⁺ → 2 AsH₃ + 3 Zn²⁺

Na₃As + 3 HBr → AsH₃ + 3 NaBr

Reactions

The understanding of the chemical properties of AsH₃ is well developed and can be anticipated based on an average of the behavior of pnictogen counterparts, such as PH₃ and SbH₃.

Thermal decomposition

Typical for a heavy hydride (e.g., SbH₃, H₂Te, SnH₄), AsH₃ is unstable with respect to its elements. In other words, it is stable kinetically but not thermodynamically.

2AsH₃ → 3H₂ + 2As

This decomposition reaction is the basis of the Marsh test, which detects elemental As.

Oxidation

Continuing the analogy to SbH₃, AsH₃ is readily oxidized by concentrated O₂ or the dilute O₂ concentration in air:

2 AsH₃ + 3 O₂ → As₂O₃ + 3 H₂O

Arsine will react violently in presence of strong oxidizing agents, such as potassium permanganate, sodium hypochlorite, or nitric acid.^[8]

Precursor to metallic derivatives

AsH₃ is used as a precursor to metal complexes of "naked" (or "nearly naked") arsenic. An example is the dimanganese species [(C₅H₅)Mn(CO)₂]₂AsH, wherein the Mn₂AsH core is planar.^[13]

Gutzeit test

A characteristic test for arsenic involves the reaction of AsH₃ with Ag⁺, called the Gutzeit test for arsenic.^[14] Although this test has become obsolete in analytical chemistry, the underlying reactions further illustrate the affinity of AsH₃ for "soft" metal cations. In the Gutzeit test, AsH₃ is generated by reduction of aqueous arsenic compounds, typically arsenites, with Zn in the presence of H₂SO₄. The evolved gaseous AsH₃ is then exposed to AgNO₃ either as powder or as a solution. With solid AgNO₃, AsH₃ reacts to produce yellow Ag₄AsNO₃, whereas AsH₃ reacts with a solution of AgNO₃ to give black Ag₃As.

Acid-base reactions

The acidic properties of the As–H bond are often exploited. Thus, AsH₃ can be deprotonated:

AsH₃ + NaNH₂ → NaAsH₂ + NH₃

Upon reaction with the aluminium trialkyls, AsH₃ gives the trimeric [R₂AlAsH₂]₃, where R = (CH₃)₃C.^[15] This reaction is relevant to the mechanism by which GaAs forms from AsH₃ (see below).

AsH₃ is generally considered non-basic, but it can be protonated by superacids to give isolable salts of the tetrahedral species [AsH₄]⁺.^[16]

Reaction with halogen compounds

Reactions of arsine with the halogens (fluorine and chlorine) or some of their compounds, such as nitrogen trichloride, are extremely dangerous and can result in explosions.^[8]

Catenation

In contrast to the behavior of PH₃, AsH₃ does not form stable chains, although diarsine (or diarsane) H₂As–AsH₂, and even triarsane H₂As–As(H)–AsH₂ have been detected. The diarsine is unstable above −100 °C.

Applications

Microelectronics applications

AsH₃ is used in the synthesis of semiconducting materials related to microelectronics and solid-state lasers. Related to phosphorus, arsenic is an n-dopant for silicon and germanium.^[8] More importantly, AsH₃ is used to make the semiconductor GaAs by chemical vapor deposition (CVD) at 700–900 °C:

Ga(CH₃)₃ + AsH₃ → GaAs + 3 CH₄

For microelectronic applications, arsine can be provided by a sub-atmospheric gas source (a source that supplies less than atmospheric pressure). In this type of gas package, the arsine is adsorbed on a solid microporous adsorbent inside a gas cylinder. This method allows the gas to be stored without pressure, significantly reducing the risk of an arsine gas leak from the cylinder. With this apparatus, arsine is obtained by applying vacuum to the gas cylinder valve outlet. For semiconductor manufacturing, this method is feasible, as processes such as ion implantation operate under high vacuum.

Chemical warfare

Since before WWII AsH₃ was proposed as a possible chemical warfare weapon. The gas is colorless, almost odorless, and 2.5 times denser than air, as required for a blanketing effect sought in chemical warfare. It is also lethal in concentrations far lower than those required to smell its garlic-like scent. In spite of these characteristics, arsine was never officially used as a weapon, because of its high flammability and its lower efficacy when compared to the non-flammable alternative phosgene. On the other hand, several organic compounds based on arsine, such as lewisite (β-chlorovinyldichloroarsine), adamsite (diphenylaminechloroarsine), Clark 1 (diphenylchloroarsine) and Clark 2 (diphenylcyanoarsine) have been effectively developed for use in chemical warfare.^[17]

Forensic science and the Marsh test

Main article: Marsh test

AsH₃ is well known in forensic science because it is a chemical intermediate in the detection of arsenic poisoning. The old (but extremely sensitive) Marsh test generates AsH₃ in the presence of arsenic.^[4] This procedure, published in 1836 by James Marsh,^[18] is based upon treating an As-containing sample of a victim's body (typically the stomach contents) with As-free zinc and dilute sulfuric acid: if the sample contains arsenic, gaseous arsine will form. The gas is swept into a glass tube and decomposed by means of heating around 250–300 °C. The presence of As is indicated by formation of a deposit in the heated part of the equipment. On the other hand, the appearance of a black mirror deposit in the cool part of the equipment indicates the presence of antimony (the highly unstable SbH₃ decomposes even at low temperatures).

The Marsh test was widely used by the end of the 19th century and the start of the 20th; nowadays more sophisticated techniques such as atomic spectroscopy, inductively coupled plasma, and x-ray fluorescence analysis are employed in the forensic field. Though neutron activation analysis was used to detect trace levels of arsenic in the mid 20th century, it has since fallen out of use in modern forensics.

Toxicology

For the toxicology of other arsenic compounds, see Arsenic, Arsenic trioxide, and Arsenic poisoning.

The toxicity of arsine is distinct from that of other arsenic compounds. The main route of exposure is by inhalation, although poisoning after skin contact has also been described. Arsine attacks hemoglobin in the red blood cells, causing them to be destroyed by the body.^[19][20]

The first signs of exposure, which can take several hours to become apparent, are headaches, vertigo, and nausea, followed by the symptoms of haemolytic anaemia (high levels of unconjugated bilirubin), haemoglobinuria and nephropathy. In severe cases, the damage to the kidneys can be long-lasting.^[1]

Exposure to arsine concentrations of 250 ppm is rapidly fatal: concentrations of 25–30 ppm are fatal for 30 min exposure, and concentrations of 10 ppm can be fatal at longer exposure times.^[3] Symptoms of poisoning appear after exposure to concentrations of 0.5 ppm. There is little information on the chronic toxicity of arsine, although it is reasonable to assume that, in common with other arsenic compounds, a long-term exposure could lead to arsenicosis.^{[citation needed]}

Arsine can cause pneumonia in two different ways either the "extensive edema of the acute stage may become diffusely infiltrated with polymorphonuclear leucocytes, and the edema may change to ringed with leucocytes, their epithelium degenerated, their walls infiltrated, and each bronchiole the center of a small focus or nodule of pneumonic consolidation", and In the second Case "the areas involved are practically always the anterior tips of the middle and upper lobes, while the posterior portions of these lobes and the whole of the lower lobes present an air-containing and emphysematous condition, sometimes with slight congestion, sometimes with none." which can result in death.^[21]

Pneumonia forming

It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.^[22]

Occupational exposure limits

Country	Limit[23]
Argentina	Confirmed human carcinogen
Australia	TWA 0.05 ppm (0.16 mg/m^3)
Belgium	TWA 0.05 ppm (0.16 mg/m^3)
Bulgaria	Confirmed human carcinogen
British Columbia, Canada	TWA 0.005 ppm (0.02 mg/m^3)
Colombia	Confirmed human carcinogen
Denmark	TWA 0.01 ppm (0.03 mg/m^3)
Egypt	TWA 0.05 ppm (0.2 mg/m^3)
France	VME 0.05 ppm (0.2 mg/m^3) VLE 0.2 ppm (0.8 mg/m^3)
Hungary	TWA 0.2 mg/m^3STEL 0.8 mg/m^3
Japan	Occupational exposure limit 0.01 ppm (0.032 mg/m^3) Continuous 0.1 ppm (0.32 mg/m^3)
Jordan	Confirmed human carcinogen
Mexico	TWA 0.05 ppm (0.2 mg/m^3)
Netherlands	MAC-TCG 0.2 mg/m^3
New Zealand	TWA 0.05 ppm (0.16 mg/m^3)
Norway	TWA 0.003 ppm (0.01 mg/m^3)
Philippines	TWA 0.05 ppm (0.16 mg/m^3)
Poland	TWA 0.2 mg/m^3 STEL 0.6 mg/m^3
Russia	STEL 0.1 mg/m^3
Singapore	Confirmed human carcinogen
South Korea	TWA 0.05 ppm (0.2 mg/m^3)
Sweden	TWA 0.02 ppm (0.05 mg/m^3)
Switzerland	MAK-week 0.05 ppm (0.16 mg/m^3)
Thailand	TWA 0.05 ppm (0.2 mg/m^3)
Turkey	TWA 0.05 ppm (0.2 mg/m^3)
United Kingdom	TWA 0.05 ppm (0.16 mg/m^3)
United States	0.05 ppm (0.2 mg/m^3)
Vietnam	Confirmed human carcinogen

See also

• Cacodylic acid
• Cacodyl oxide
• Devarda's alloy, also used to produce arsine in the lab
• List of highly toxic gases
• Scheele's Green, a pigment popularly used in the early 19th century

References

1. NIOSH Pocket Guide to Chemical Hazards. "#0040". National Institute for Occupational Safety and Health (NIOSH).
2. Levvy, G.A. (1946). "The Toxicity of Arsine Administered by Intraperitoneal Injection". British Journal of Pharmacology and Chemotherapy. 1 (4): 287–290. doi:10.1111/j.1476-5381.1946.tb00049.x. PMC 1509744. PMID 19108099.
3. "Arsine". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
4. Holleman, A. F.; Wiberg, E. (2001) Inorganic Chemistry Academic Press: San Diego, ISBN 0-12-352651-5.
5. Greaves, Ian; Hunt, Paul (2010). "Ch. 5 Chemical Agents". Responding to Terrorism. A Medical Handbook. Elsevier. pp. 233–344. doi:10.1016/B978-0-08-045043-8.00005-2. ISBN 978-0-08-045043-8. While arsine itself is odourless, its oxidation by air may produce a slight, garlic-like scent. However, it is lethal in concentrations far lower than those required to produce this smell.
6. "Medical Management Guidelines for Arsine (AsH₃)". Agency for Toxic Substances & Disease Registry. Archived from the original on January 24, 2012.
7. Hartman, Robert James (1947). Briscoe, Herman Thompson (ed.). Colloid Chemistry (2 ed.). Houghton Mifflin Company. p. 124.
8. Institut National de Recherche et de Sécurité (2000). Fiche toxicologique nº 53: Trihydrure d'arsenic (PDF) (Report) (in French). Archived from the original (PDF) on 2006-11-26. Retrieved 2006-09-06.
9. Nielsen, H. H. (1952). "The Molecular Structure of Arsine". The Journal of Chemical Physics. 20 (12): 1955–1956. Bibcode:1952JChPh..20.1955N. doi:10.1063/1.1700347.
10. Bellama, J. M.; MacDiarmid, A. G. (1968). "Synthesis of the Hydrides of Germanium, Phosphorus, Arsenic, and Antimony by the Solid-Phase Reaction of the Corresponding Oxide with Lithium Aluminum Hydride". Inorganic Chemistry. 7 (10): 2070–2. doi:10.1021/ic50068a024.
11. Scheele, Carl Wilhelm (1775) "Om Arsenik och dess syra" Archived 2016-01-05 at the Wayback Machine (On arsenic and its acid), Kongliga Vetenskaps Academiens Handlingar (Proceedings of the Royal Scientific Academy [of Sweden]), 36: 263-294. From p. 290: "Med Zinck. 30. (a) Denna år den endaste af alla så hela som halfva Metaller, som i digestion met Arsenik-syra effervescerar." (With zinc. 30. (a) This is the only [metal] of all whole- as well as semi-metals that effervesces on digestion with arsenic acid.) Scheele collected the arsine and put a mixture of arsine and air into a cylinder. From p. 291: "3:0, Då et tåndt ljus kom når o̊pningen, tåndes luften i kolfven med en småll, lågan for mot handen, denna blef o̊fvedragen med brun fårg, ... " (3:0, Then as [the] lit candle came near the opening [of the cylinder], the gases in [the] cylinder ignited with a bang; [the] flame [rushed] towards my hand, which became coated with [a] brown color, ... )
12. "Arsine" in Handbook of Preparative Inorganic Chemistry, 2nd ed., G. Brauer (ed.), Academic Press, 1963, NY, Vol. 1. p. 493.
13. Herrmann, W. A.; Koumbouris, B.; Schaefer, A.; Zahn, T.; Ziegler, M. L. (1985). "Generation and Complex Stabilization of Arsinidene and Diarsine Fragments by Metal-Induced Degradation of Monoarsine". Chemische Berichte. 118 (6): 2472–88. doi:10.1002/cber.19851180624.
14. King, E. J. (1959) Qualitative Analysis and Electrolytic Solutions Harcourt, Brace, and World; New York
15. Atwood, D. A.; Cowley, A. H.; Harris, P. R.; Jones, R. A.; Koschmieder, S. U.; Nunn, C. M.; Atwood, J. L.; Bott, S. G. (1993). "Cyclic Trimeric Hydroxy, Amido, Phosphido, and Arsenido Derivatives of aluminum and gallium. X-ray Structures of [tert-Bu₂Ga(m-OH)]₃ and [tert-Bu₂Ga(m-NH₂)]₃". Organometallics. 12: 24–29. doi:10.1021/om00025a010.
16. R. Minkwitz, R.; Kornath, A.; Sawodny, W.; Härtner, H. (1994). "Über die Darstellung der Pnikogenoniumsalze AsH₄⁺SbF₆⁻, AsH₄⁺AsF₆⁻, SbH₄⁺SbF₆⁻". Zeitschrift für Anorganische und Allgemeine Chemie (in German). 620 (4): 753–756. doi:10.1002/zaac.19946200429.
17. Suchard, Jeffrey R. (March 2006). "CBRNE — Arsenicals, Arsine". EMedicine. Archived from the original on 2006-06-23. Retrieved 2006-09-05.
18. Marsh, James (1836). "Account of a method of separating small quantities of arsenic from substances with which it may be mixed". Edinburgh New Philosophical Journal. 21: 229–236.
19. Fowler B. A.; Weissberg J. B. (1974). "Arsine poisoning". New England Journal of Medicine. 300 (22): 1171–1174. doi:10.1056/NEJM197411282912207. PMID 4608634.
20. Hatlelid K. M. (1996). "Reactions of Arsine with Hemoglobine". Journal of Toxicology and Environmental Health Part A. 47 (2): 145–157. Bibcode:1996JTEHA..47..145H. doi:10.1080/009841096161852. PMID 8598571.
21. "Collected Studies on the Pathology of War Gas Poisoning, from the Department of Bacteriology and Pathology, Medical Science Section, Chemical Warfare Service, under the direction of M. C. Winternitz, major, M. C., U. S. A. Yale University Press". books.google.com. Yale University press. 1920. Retrieved 28 September 2022.
22. 40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities (PDF) (Report) (July 1, 2008 ed.). Government Printing Office. Archived from the original (PDF) on February 25, 2012. Retrieved October 29, 2011.
23. "Arsine". RTECS. National Institute for Occupational Safety and Health (NIOSH). Archived from the original on 2017-06-08. Retrieved 2017-09-08.

External links

• International Chemical Safety Card 0222
• IARC Monograph "Arsenic and Arsenic Compounds"
• NIOSH Pocket Guide to Chemical Hazards
• Institut national de recherche et de sécurité (2000). "Trihydrure d'arsenic." Fiche toxicologique n° 53. Paris:INRS. (in French)
• Data on arsine from Air Liquide