Bismuth(III) iodide is the
inorganic compound
An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bondsthat is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''.
Inorgan ...
with the
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...
Bi I3. This gray-black salt is the product of the reaction of bismuth and iodine, which once was of interest in
qualitative inorganic analysis.
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]
Bismuth(III) iodide adopts a distinctive crystal structure, with
iodide centres occupying a
hexagonally closest-packed lattice, and bismuth centres occupying either none or two-thirds of the octahedral holes (alternating by layer), therefore it is said to occupy one third of the total octahedral holes.
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Synthesis
Bismuth(III) iodide forms upon heating an intimate mixture of iodine and bismuth powder:
:2Bi + 3I
2 → 2BiI
3
BiI
3 can also be made by the reaction of
bismuth oxide with aqueous
hydroiodic acid:
:Bi
2O
3(s) + 6HI(aq) → 2BiI
3(s) + 3H
2O(l)
Reactions
Since bismuth(III) iodide is insoluble in water, an aqueous solution can be tested for the presence of Bi
3+ ions by adding a source of iodide such as
potassium iodide. A black
precipitate of bismuth(III) iodide indicates a positive test.
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]
Bismuth(III) iodide forms iodobismuth(III) anions when heated with halide donors:
[
]
:2
NaI + BiI
3 → Na
2 iI5
Bismuth(III) iodide catalyzes the
Mukaiyama aldol reaction. Bi(III) is also used in a
Barbier type allylation of carbonyl compounds in combination with a reducing agent such as
zinc
Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...
or
magnesium
Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...
.
References
{{Iodides
Bismuth iodide
Iodides
Metal halides