Iodine pentoxide is the
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
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 betwee ...
I
2O
5. This
iodine oxide
Iodine oxides are chemical compounds of oxygen and iodine. Iodine has only two stable oxides which are isolatable in bulk, iodine tetroxide and iodine pentoxide, but a number of other oxides are formed in trace quantities or have been hypothesize ...
is the
anhydride
An organic acid anhydride is an acid anhydride that is an organic compound. An acid anhydride is a compound that has two acyl groups bonded to the same oxygen atom. A common type of organic acid anhydride is a carboxylic anhydride, where the pa ...
of
iodic acid
Iodic acid is a white water-soluble solid with the chemical formula . Its robustness contrasts with the instability of chloric acid and bromic acid. Iodic acid features iodine in the oxidation state +5 and is one of the most stable oxo-acids of ...
, and the only stable oxide of iodine. It is produced by dehydrating iodic acid at 200 °C in a stream of dry air:
[
:2HIO3 → I2O5 + H2O
]
Structure
I2O5 is bent with an I–O–I angle of 139.2°, but the molecule has no mirror plane so its symmetry
Symmetry (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definit ...
is C2 rather than C2v. The terminal I–O distances are around 1.80 Å and the bridging I–O distances are around 1.95 Å.
Reactions
Iodine pentoxide easily oxidises carbon monoxide
Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
to carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
at room temperature:
:5 CO + I2O5 → I2 + 5 CO2
This reaction can be used to analyze the concentration of CO in a gaseous sample.
I2O5 forms iodyl salts, 2+">O2+ with SO3 and S2O6F2, but iodosyl salts, +">O+ with concentrated sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
.
Iodine pentoxide decomposes to iodine (vapor) and oxygen when heated to about 350 °C.[G. Baxter and G. Tilley, "A Revision of the Atomic Weights of Iodine and Silver," ''The Chemical News and Journal of Industrial Science; Volumes 99-100'', Royal Society Anniversary Meeting, December 3, 1909, p. 276.]
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References
{{DEFAULTSORT:Iodine Pentoxide
Iodine compounds
Oxides
Acidic oxides
Oxidizing agents