Reaction of gallium arsenide with concentrated acids: formation of arsine.
Crystalline particles of gallium arsenide (GaAs) (approximately 2 microns in diameter) react with concentrated hydrochloric acid (HCl) (11.6 to 9 M) to form highly toxic arsine (AsH3) gas. None of the other strong acids that were investigated reacted with gallium arsenide to form AsH3. A spectrophotometric method, based on the reaction of AsH3 with silver diethyldithiocarbamate in a chloroform solution containing morpholine, was used to detect AsH3 gas dissolved in aqueous solutions and to determine the AsH3 gas that was liberated by the reaction of GaAs with HCl. Active sites on the gallium arsenide surface initiate the reaction that forms AsH3 gas. Absorption of oxygen or ions from solution on these active sites inhibits the formation of AsH3.
Scott
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Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson 85721.
Carter
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Fernando
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D001151:Arsenic / Q000138:chemical synthesis*; D001152:Arsenicals; D005708:Gallium; D005740:Gases; D006851:Hydrochloric Acid; D010100:Oxygen
D001152:Arsenicals; D005740:Gases; C043055:gallium arsenide; D005708:Gallium; D001151:Arsenic; D006851:Hydrochloric Acid; D010100:Oxygen; C006633:arsine