7784-42-1

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Safety Profile

Confirmed human carcinogen.Poison by inhalation. Human red blood cell,gastrointestinal system, central nervous system, and othersystemic effects by inhalation. Flammable when exposedto flame. Moderately explosive when exposed to Cl2,HNO3, (K + NH3),

Upstream product

• 7439-95-4 magnesium 
• 7732-18-5 water 
• 7784-34-1 arsenic trichloride 
• 7664-93-9 sulfuric acid 
• 1333-74-0 hydrogen 
• 141-53-7 sodium formate 
• 7778-39-4 orthoarsenic acid 
• 7440-66-6 zinc 
• 1310-73-2 sodium hydroxide 
• 13937-35-4 AsH₂^(1-) 
• 7783-06-4 hydrogen sulfide 
• 60189-99-3 sodium dihydrogenarsenite 
• 13464-58-9 arsenous acid 

Downstream Products

• 14644-45-2 AsH₂ 
• 13464-58-9 arsenous acid 
• 61219-26-9 manganese monoarsenide 

Relevant academic research and scientific papers

Pnictogen-hydride activation by (silox)3Ta (silox = tBu3SiO); Attempts to circumvent the constraints of orbital symmetry in N2 activation

Activation of N2 by (silox)3Ta (1, silox = tBu3SiO) to afford (silox)3Ta=N-N=Ta(silox) 3 (12-N2) does not occur despite ΔG°cald = -55.6 kcal/mol because of constraints of orbital symmetry, prompting efforts at an independent synthesis that included a study of REH2 activation (E = N, P, As). Oxidative addition of REH 2 to 1 afforded (silox)3HTaEHR (2-NHR, R = H, Me, nBu, C6H4-p-X (X = H, Me, NMe2); 2-PHR, R = H, Ph; 2-AsHR, R = H, Ph), which underwent 1,2-H2- elimination to form (silox)3Ta=NR (1=NR; R = H, Me, nBu, C6H4-p-X (X = H (X-ray), Me, NMe2, CF 3)), (silox)3Ta=PR (1=PR; R = H, Ph), and (silox) 3Ta=AsR (1=AsR; R = H, Ph). Kinetics revealed NH bond-breaking as critical, and As > N > P rates for (silox)3HTaEHPh (2-EHPh) were attributed to (1) ΔG°calc(N) calc(P) ～ ΔG°calc(As); (2) similar fractional reaction coordinates (RCs), but with RC shorter for N P～As. Calculations of the pnictidenes aided interpretation of UV-vis spectra. Addition of H2NNH2 or H2N-N(cNC2H3Me) to 1 afforded 1=NH, obviating these routes to 12-N2, and formation of (silox)3MeTaNHNH2 (4-NHNH2) and (silox) 3MeTaNH(-cNCHMeCH2) (4-NH(azir)) occurred upon exposure to (silox)3Ta=CH2 (1=CH2). Thermolyses of 4-NHNH2 and 4-NH(azir) yielded [(silox)2TaMe](μ- NαHNβ)(μ-NγHN δH)[Ta(silox)2] (5) and [(silox)3MeTa] (μ-η2-N,N: η1-C-NHNHCH2CH 2CH2)[Ta(κ-O,C-OSitBu2CMe 2CH2)(silox)2] (7, X-ray), respectively. (silox)3Ta=CPPh3 (1=CPPh3, X-ray) was a byproduct from Ph3PCH2 treatment of 1 to give 1=CH 2. Addition of Na(silox) to [(THF)2Cl3Ta] 2(μ-N2) led to [(silox)2ClTa](μ-N 2) (8-Cl), and via subsequent methylation, [(silox) 2MeTa]2(μ-N2) (8-Me); both dimers were thermally stable. Orbital symmetry requirements for N2 capture by 1 and pertinent calculations are given.

Synthesis of volatile inorganic hydrides by electrochemical method

Published data and results of our investigations on the problem of electrochemical synthesis of arsenic, phosphorus, and germanium hydrides are generalized. The results of the developments of the physicochemical bases of arsine synthesis by electrochemical reduction of arsenic acid, phosphine by reduction of white phosphorus in organic solvents, and monogermane by reduction of germanate in basic conditions are reported. The current yield of hydrides is 95, 90, and 40%, respectively. The promising guidelines of the practical use of electrochemical methods of the synthesis of the hydrides in the manufacture of semiconductor materials for microelectronics, optics, and laser engineering are discussed. The development of an arsine generator attracts considerable interest, which can serve as a basis for an aggregative continuous apparatus used in complex flow charts of manufacture of semiconductor materials.

GASEOUS DIELECTRICS WITH LOW GLOBAL WARMING POTENTIALS

A dielectric gaseous compound which exhibits the following properties: a boiling point in the range between about ?20° C. to about ?273° C.; non-ozone depleting; a GWP less than about 22,200; chemical stability, as measured by a negative standard enthalpy of formation (dHf0); a toxicity level such that when the dielectric gas leaks, the effective diluted concentration does not exceed its PEL; and a dielectric strength greater than air.

Electrochemical reduction of As(III) in acid media

Measurements of the cathode potentials of different electrode materials in the galvanostatic electrolysis of As2O3 solutions in sulfuric acid indicate that the Pb cathode ensures the most stable negative potential, favorable for AsH3 formation. Preparative electrolyses confirm stability of the arsine yield in a series of experiments. The current efficiency for arsine on the Pb cathode is 60-70%. The byproduct of this process is As0, with a current efficiency of about 2%. We have designed and tested an electrolyzer with improved hydrodynamics, which makes it possible to avoid the formation of dead zones and to prevent the cathode chamber from being clogged.

Laser spectroscopy and dynamics of the jet-cooled AsH2 free radical

The A2A1-X2B1 electronic transition of the jet-cooled AsH2 free radical has been studied by laser-induced fluorescence (LIF), wavelength-resolved emission, and fluorescence lifetime measurements. The radical was produced by a pulsed electric discharge through a mixture of arsine (AsH3) and high pressure argon at the exit of a pulsed valve. Nine vibronic bands wereidentified by LIF spectroscopy in the 505-400 nm region, including a lo ng progression in the bending mode and two bands (101 and 101201) involving the excited state As-H symmetric stretch. Single vibronic level emission spectra showed similar activity in the bending and symmetric stretching frequencies of the ground state. High-resolution spectra of the 000 band exhibited large spin splittings and small, resolved arsenic hyperfine splittings, due to a substantial Fermi contact interaction in the excited state. The rotational constants obtained in the analysis gave effective molecular structures of r″0 = 1.5183(1) ?, θ″0=90.75(1) ° and r′0=1.4830(1) ?, θ′0= 123.10(2)°. The excited state fluorescence lifetimes vary dramatically with rovibronicstate, from a single value of 1.4 μs to many with lifetimes less tha n 10 ns, behavior which the authors interpret as signaling the onset of a predissociative process near the zero-point level of the ground state.

Spectrophotometric determination of arsenic via nanogold formation in micellar medium

Colloidal gold nanoparticles are formed in aqueous anionic micellar medium by the quantitative reduction of chloroauric acid (HAuCl4) by arsine (AsH3) gas produced from arsenic bearing sample water. The absorbance of the pink gold sol (λmax at 530 nm) is a measure of arsenic concentration present in the sample. Both, As(III) and As(V) either present individually or in mixture could be determined. The molar absorptivity is 6.1×103 lit mol-1 cm-1 and the Sandell sensitivity is 1.28×10-2 μg cm-2. The gold particles, as observed from the transmission electron microscopy analysis, are spherical in nature, the average size being 14±5 nm. The linear dynamic range (LDR) for the arsenic determination is 0-0.5 ppm (0-6.67×10 -6 M). The limit of detection (LOD) is 0.005 ppm. The 95% confidence limit for 0.2 ppm of arsenic is 0.207±0.007 ppm (for 10 replicates). The relative standard deviation (RSD) is 2+/Fe3+, Ca2+/Mg 2+, PO4-3, SiO3-2, NO3-, Cl-, SO4-2, humic acid, common herbicides/pesticides like 2,4-D, endosulfan, atrazine, etc. and can be applied for the determination of total arsenic concentration in real water samples. The results are in good agreement with the SDDC method. The toxic and volatile organic solvents used for silver diethyldithiocarbamate method could be avoided in this method and hence it is safer, much easier and more reproducible.

Electrochemical preparation of H2S and H2Se

H2S and H2Se have been electrolytically prepared by electrolysis in aqueous H2SO4 solutions of composite cathodes made of S or Se and graphite. The efficiencies depended strongly on the electrolyte composition, in particular on the acid concentration and presence of K+. Faradaic efficiencies of 80% were obtained in dilute (0.05 M) acid, and this increased to 100% with added K2SO4. The efficiencies dropped drastically in concentrated acid (>a few moles). H 2Te and AsH3 generation were also briefly studied for comparison. The mechanisms of hydride formation are discussed. Both the reaction of nascent hydrogen with the free element and direct reduction of the element are considered. The latter is believed to be the dominant mechanism.

Synthesis and TG/DTA study on two new metallo(VI)-arsenato(V) heteropolyacids containing vanadium(V)

An improved method for the synthesis of two heteropolyacids of the same type: H5[AsMo10V2O40]· 13H2O and H5[AsW10V2O40] ·16H2O was elaborated. Th

Etching AlAs with HF for epitaxial lift-off applications

The epitaxial lift-off process allows the separation of a thin layer of III/V material from the substrate by selective etching of an intermediate AlAs layer with HF In a theory proposed for this process, it was assumed that for every mole of AIAs dissolved three moles of H2 gas are formed. In order to verify this assumption the reaction mechanism and stoichiometry were investigated in the present work. The solid, solution and gaseous reaction products of the etch process have been examined by a number of techniques, It was found that aluminum fluoride is formed, both in the solid form as well as in solution. Furthermore, instead of H2 arsine (AsH3) is formed in the etch process. Some oxygen-related arsenic compounds like AsO, AsOH, and AsO2 have also been detected with gas chromatography/mass spectroscopy. The presence of oxygen in the etching environment accelerates the etching process, while a total absence of oxygen resulted in the process coming to a premature halt. It is argued that, in the absence of oxygen, the etching surface is stabilized, possibly by the sparingly soluble A1F3 or by solid arsenic.

Electrochemical preparation of arsenic and its compounds

Electrochemical processes are used to recover elemental arsenic from NaH2AsO3 solutions, oxidize As2O3 suspensions to arsenic acid, and reduce arsenic acid to arsine. The electrolysis conditions are optimized for obtaining elemental arsenic: 0.8-0.9 M NaH 2AsO3, 0.03-0.05 A/cm2, 20-25°C. The introduction of tetraalkylammonium salts containing C9-C12 substituents, e.g., trimethylcetylammonium bromide, is shown to stabilize the current efficiency in terms of As at a level of 45-50%. The current efficiency of copper cathodes attains 89% in 1-2 M H3AsO4 solutions at a current density of 0.2 A/cm2. In the electrosynthesis of arsenic acid, quantitative substance and current yields are achieved in 2-3 M HCl solutions. Low-waste processes are proposed for preparing arsenic, H 3AsO4, and As2O5 from As 2O3. The resulting arsenic is suitable for producing high-purity (99.9999%) material. The physicochemical processes underlying arsine generation are examined, and a bench-scale electrochemical arsine generator is described which can be used in the manufacturing of semiconductor materials.