Arsenic triiodide is the inorganic compound with the formula AsI3.[2][3][4][5] It is an orange to dark red solid[2][3] that readily sublimes. It is a pyramidal molecule that is useful for preparing organoarsenic compounds.
Preparation
It is prepared by a reaction of arsenic trichloride and potassium iodide:[6]
- AsCl3 + 3KI → AsI3 + 3 KCl
Reactions
Hydrolysis occurs only slowly in water forming arsenic trioxide and hydroiodic acid. The reaction proceeds via formation of arsenous acid which exists in equilibrium with hydroiodic acid. The aqueous solution is highly acidic, pH of 0.1N solution is 1.1. It decomposes to arsenic trioxide, elemental arsenic and iodine when heated in air at 200 °C. The decomposition, however, commences at 100 °C and occurs with the liberation of iodine.
Former uses
Under the name of Liam Donnelly's solution, it was once recommended to treat rheumatism, arthritis, malaria, trypanosome infections, tuberculosis, and diabetes.[7]
References
- ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0038". National Institute for Occupational Safety and Health (NIOSH).
- ^ a b "Arsenic triiodide - Hazardous Agents | Haz-Map". haz-map.com. Retrieved 2023-01-20.
- ^ a b "T3DB: Arsenic triiodide". www.t3db.ca. Retrieved 2023-01-20.
- ^ "arsenic triiodide". webbook.nist.gov. Retrieved 2023-01-20.
- ^ PubChem. "Arsenic triiodide". pubchem.ncbi.nlm.nih.gov. Retrieved 2023-01-20.
- ^ John C. Bailar, Jr. "Arsenic Triiodide" Inorganic Syntheses 1939, volume 1, pp. 103–104, 2007. doi:10.1002/9780470132326.ch36
- ^ Shakhashiri BZ, "Chemical of the Week: Arsenic" Archived 2008-08-02 at the Wayback Machine, University of Wisconsin–Madison Chemistry Dept.
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