Aluminum iodide, AlI3, is formed by the reaction of aluminum and iodine, which is the combining of aluminum hydroxide with hydroiodic acid. It is an inorganic Lewis acid, a special type of chemical capable of accepting an electron pair, from the binary compound group. As with other varieties of aluminum compounds, aluminum iodide can absorb water from the air. In many cases, it is described as aluminum salt or hydroiodic acid. Aluminum iodide is white with a yellowish hue. Along with dissolving in water, aluminum iodide can be absorbed by alcohol, ether, carbon sulfide, and pyridine, a colorless liquid from coal tar.
Characteristics of Aluminum Iodide
- It reacts with sulfuric acid.
- When exposed to moisture in the air, it slightly decomposes into a subsalt.
- Heated aluminum iodide solution forms an aluminum hydroxide precipitate.
- In water, hydrolysis of a cation takes place forming an acid medium.
- With diluted alkalis, it forms an aluminum hydroxide.
- It can be decomposed by the formation of a tetrahydroxalluminate.
Sometimes, in organic chemistry, there is a need to speed up a reaction with a catalyst. Aluminum iodide breaks the bonds between carbon and oxygen or nitrogen and oxygen. Aluminum ions and iodide ions replace what is removed. It can also remove oxygen atoms from epoxides, a cyclic ether.
Some of the uses for aluminum iodide involve veterinary medicine and pigs. When pigs have pneumonia, an aerosol version of aluminum iodide is sprayed on them. It is also used in horse and cattle barns to kill germs and disinfect enclosures. Spraying it in areas with calves and pigs, it can protect them from any susceptibility to respiratory diseases.
Aluminum iodide is high in antibacterial agents but has little effect on the mucus membranes. New uses are being studied to increase pathogenic and therapeutic effects.
Contact with aluminum iodide causes burns to the skin and eyes as well as damage to the mucosae of the digestive system. People allergic to aluminum compounds will have a severely adverse reaction to it.
As with several of the aluminum compounds, aluminum iodide must be handled very carefully in a well-sealed fume cupboard. To dispose of a mixture of aluminum iodide, it should be poured into sodium hydroxide and left to set until it dissolves.