Editing Arsine (section)

==Reactions==
The understanding of the chemical properties of AsH<sub>3</sub> is well developed and can be anticipated based on an average of the behavior of [[pnictogen]] counterparts, such as  [[phosphine|PH<sub>3</sub>]] and [[stibine|SbH<sub>3</sub>]].

===Thermal decomposition===
Typical for a heavy hydride (e.g., [[stibine|{{chem2|SbH3}}]], {{chem2|H2Te}}, {{chem2|SnH4}}), {{chem2|AsH3}} is unstable with respect to its elements. In other words, it is stable kinetically but not thermodynamically.
::{{chem2|2AsH3 -> 3H2 + 2As}}

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

===Oxidation===
Continuing the analogy to SbH<sub>3</sub>, AsH<sub>3</sub> is readily [[oxidation|oxidized]] by concentrated O<sub>2</sub> or the dilute O<sub>2</sub> concentration in air:
::2 AsH<sub>3</sub> + 3 O<sub>2</sub> → As<sub>2</sub>O<sub>3</sub> + 3 H<sub>2</sub>O

Arsine will react violently in presence of strong oxidizing agents, such as [[potassium permanganate]], [[sodium hypochlorite]], or [[nitric acid]].<ref name="INRS"/>

===Precursor to metallic derivatives===
AsH<sub>3</sub> is used as a precursor to metal complexes of "naked" (or "nearly naked") arsenic. An example is the dimanganese species [(C<sub>5</sub>H<sub>5</sub>)Mn(CO)<sub>2</sub>]<sub>2</sub>AsH, wherein the Mn<sub>2</sub>AsH core is planar.<ref name="Herrmann">{{cite journal|last1=Herrmann |first1=W. A. |last2=Koumbouris |first2=B. |last3=Schaefer |first3=A. |last4=Zahn |first4=T. |last5=Ziegler |first5=M. L. |title=Generation and Complex Stabilization of Arsinidene and Diarsine Fragments by Metal-Induced Degradation of Monoarsine|journal=Chemische Berichte|date=1985|volume= 118 |pages= 2472–88|doi=10.1002/cber.19851180624|issue=6}}</ref>

===Gutzeit test===
A characteristic test for arsenic involves the reaction of AsH<sub>3</sub> with Ag<sup>+</sup>, called the Gutzeit test for arsenic.<ref name="King">King, E. J. (1959) ''Qualitative Analysis and Electrolytic Solutions'' Harcourt, Brace, and World; New York</ref> Although this test has become obsolete in [[analytical chemistry]], the underlying reactions further illustrate the affinity of AsH<sub>3</sub> for "soft" metal cations. In the Gutzeit test, AsH<sub>3</sub> is generated by reduction of aqueous arsenic compounds, typically [[arsenite]]s, with Zn in the presence of H<sub>2</sub>SO<sub>4</sub>. The evolved gaseous AsH<sub>3</sub> is then exposed to AgNO<sub>3</sub> either as powder or as a solution. With solid AgNO<sub>3</sub>, AsH<sub>3</sub> reacts to produce yellow Ag<sub>4</sub>AsNO<sub>3</sub>, whereas AsH<sub>3</sub> reacts with a solution of AgNO<sub>3</sub> to give black Ag<sub>3</sub>As.

===Acid-base reactions===
The acidic properties of the As–H bond are often exploited. Thus, AsH<sub>3</sub> can be deprotonated:
::AsH<sub>3</sub> + NaNH<sub>2</sub> → NaAsH<sub>2</sub> + NH<sub>3</sub>

Upon reaction with the aluminium trialkyls, AsH<sub>3</sub> gives the trimeric [R<sub>2</sub>AlAsH<sub>2</sub>]<sub>3</sub>, where R = (CH<sub>3</sub>)<sub>3</sub>C.<ref name="Atwood">{{cite journal|author1=Atwood, D. A. |author2=Cowley, A. H. |author3=Harris, P. R. |author4=Jones, R. A. |author5=Koschmieder, S. U. |author6=Nunn, C. M. |author7=Atwood, J. L. |author8=Bott, S. G. |title=Cyclic Trimeric Hydroxy, Amido, Phosphido, and Arsenido Derivatives of aluminum and gallium. X-ray Structures of [tert-Bu<sub>2</sub>Ga(m-OH)]<sub>3</sub> and [tert-Bu<sub>2</sub>Ga(m-NH<sub>2</sub>)]<sub>3</sub>|journal=Organometallics|date=1993|volume=12 |pages= 24–29|doi=10.1021/om00025a010}}</ref> This reaction is relevant to the mechanism by which GaAs forms from AsH<sub>3</sub> (see below).

AsH<sub>3</sub> is generally considered non-basic, but it can be protonated by [[superacid]]s to give isolable salts of the tetrahedral species [AsH<sub>4</sub>]<sup>+</sup>.<ref name="Minkwitz">{{cite journal|author1=R. Minkwitz, R. |author2=Kornath, A. |author3=Sawodny, W. |author4=Härtner, H. |title=Über die Darstellung der Pnikogenoniumsalze AsH<sub>4</sub><sup>+</sup>SbF<sub>6</sub><sup>−</sup>, AsH<sub>4</sub><sup>+</sup>AsF<sub>6</sub><sup>−</sup>, SbH<sub>4</sub><sup>+</sup>SbF<sub>6</sub><sup>−</sup>|journal=Zeitschrift für Anorganische und Allgemeine Chemie|volume= 620 |pages= 753–756|doi=10.1002/zaac.19946200429|date=1994|issue=4|language=de}}</ref>

===Reaction with halogen compounds===
Reactions of arsine with the [[halogen]]s ([[fluorine]] and [[chlorine]]) or some of their compounds, such as [[nitrogen trichloride]], are extremely dangerous and can result in explosions.<ref name="INRS"/>

===Catenation===
In contrast to the behavior of PH<sub>3</sub>, AsH<sub>3</sub> does not form stable chains, although diarsine (or diarsane) H<sub>2</sub>As–AsH<sub>2</sub>, and even triarsane H<sub>2</sub>As–As(H)–AsH<sub>2</sub> have been detected. The diarsine is unstable above −100&nbsp;°C.