Iridium(III) iodide is an
iodide
An iodide ion is I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine deficiency ...
of
iridium
Iridium is a chemical element; it has the symbol Ir and atomic number 77. This very hard, brittle, silvery-white transition metal of the platinum group, is considered the second-densest naturally occurring metal (after osmium) with a density ...
, with the chemical formula of IrI
3.
Preparation
Iridium(III) iodide can be obtained by reducing
iridium(IV) iodide with hydrogen at 210 °C. It can also be formed by the reaction of
iridium dioxide
Iridium(IV) oxide, IrO2, is the only well-characterised oxide of iridium. It is a blue-black solid, used with other rare oxides to coat anodes.
Synthesis
As described by its discoverers, it can be formed by treating the green form of iridium t ...
or
iridium(III) hydroxide with
hydrogen iodide
Hydrogen iodide (HI) is a diatomic molecule and hydrogen halide. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a strong acid. Hydrogen iodide and hydroiodic acid are, however, different in that the former is a gas und ...
.
Chemical properties
Iridium(III) iodide is a dark brown solid that is insoluble in water.
It is
monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in t ...
like
chromium trichloride.
Its trihydrate is yellow and can be dehydrated into the dihydrate or anhydrous form on heating. Iridium(III) iodide also has a monohydrate.
References
{{Iodides
Iridium compounds
Iodides
Platinum group halides