Iodoform
Iodoform is the organoiodine compound with the chemical formula. It is a pale yellow, crystalline, volatile substance, with a penetrating and distinctive odor and, analogous to chloroform, sweetish taste. It is occasionally used as a disinfectant.
Naming
The name iodoform originates with the "formyle radical," an archaic term for the HC moiety, and is retained for historical consistency. A full, modern name is triiodomethane. Another possible name is "carbon hydride triiodide". The "hydride" in the latter is sometimes omitted, though the IUPAC recommends against doing so, as "carbon triiodide" could also mean .Structure
The molecule adopts a tetrahedral geometry with C3v symmetry.Synthesis and reactions
The synthesis of iodoform was first described by Georges-Simon Serullas in 1822, by reactions of iodine vapour with steam over red-hot coals, and also by reaction of potassium with ethanolic iodine in the presence of water; and at much the same time independently by John Thomas Cooper. It is synthesized in the haloform reaction by the reaction of iodine and sodium hydroxide with any one of these four kinds of organic compounds: a methyl ketone, acetaldehyde, ethanol, and certain secondary alcohols.The reaction of iodine and base with methyl ketones is so reliable that the iodoform test is used to probe the presence of a methyl ketone. This is also the case when testing for specific secondary alcohols containing at least one methyl group in alpha-position.
Some reagents convert iodoform to diiodomethane. Conversion to carbon dioxide is also possible. Iodoform reacts with aqueous silver nitrate to produce carbon monoxide. When treated with powdered elemental silver the iodoform is reduced, producing acetylene. Upon heating iodoform decomposes to produce diatomic iodine, hydrogen iodide gas, and carbon.