Iodine pentoxide
| Names | |
|---|---|
| IUPAC name
Iodine pentoxide
| |
| Preferred IUPAC name
Iodine pentoxide | |
| Systematic IUPAC name
Iodine pentoxide | |
| Other names
Diiodine pentoxide
Diiodopentoxide Iodic anhydride Iodine pentaoxide Iodine(V) oxide Iodopentoxide Iodyl iodate | |
| Properties | |
| I2O5 | |
| Molar mass | 333.81 g/mol |
| Appearance | White solid |
| Odor | Odorless (pure) Iodine (impure) |
| Density | 5.08 g/cm3 (20 °C) |
| Melting point | 350 °C (662 °F; 623 K) (decomposes) |
| Boiling point | Decomposes |
| 187 g/100 ml (hydrolysis) | |
| Solubility | Soluble in nitric acid Insoluble in acetonitrile, carbon disulfide, chloroform, diethyl ether, ethanol |
| Vapor pressure | ~0 mmHg |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Flash point | Non-flammable |
| Related compounds | |
| Related compounds
|
Dichlorine heptoxide Dibromine pentoxide |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Iodine pentoxide is the chemical compound with the formula I2O5. This iodine oxide is the anhydride of iodic acid, and the only stable oxide of iodine.
Contents
[hide]Properties
Chemical
Iodine pentoxide hydrolyzes in water to form iodic acid.[1]
- I2O5 + H2O → 2 HIO3
Iodine pentoxide easily oxidizes carbon monoxide to carbon dioxide at room temperature. Conc. sulfuric acid may be needed to activate the reaction.
- 5 CO + I2O5 → I2 + 5 CO2
This reaction, called Ditte's reaction, can be used to analyze the concentration of CO in a gaseous sample.
Iodine pentoxide will react with hydrogen sulfide, forming sulfur dioxide:
- 3 I2O5 + 5 H2S → 3 I2 + 5 SO2 + 5 H2O
Elemental sulfur will also oxidize to sulfur dioxide, though strong heat is required to initiate the reaction.
- 2 I2O5 + 5 S → 5 I2 + 2 SO2
A mixture of carbon and iodine pentoxide will ignite with a drop of conc. sulfuric acid is added to it.
Iodine pentoxide reacts violently with hydrazine at standard conditions, producing HI.[2]
Mixing iodine pentoxide with lithium borohydride is sufficient to ignite said mixture.
Iodine pentoxide will oxidize hydrogen chloride aka hydrochloric acid to chlorine, while forming tetrachloroiodic acid.
- I2O5 + 12 HCl → 2 HICl4 + 2 Cl2 + 5 H2O
I2O5 forms iodyl salts, [IO2+], with sulfur trioxide and bis(fluorosulfuryl)peroxide, but iodosyl salts, [IO+], with concentrated sulfuric acid.
Physical
Iodine pentoxide is a white dense solid, that readily hydrolyzes in water. The pure compound is odorless, but exposure to impurities will release minute amounts of elemental iodine, giving the sample a faint iodine-like odor.
Availability
Iodine pentoxide can be bought from chemical suppliers.
Preparation
Iodine pentoxide is produced by dehydrating iodic acid at 200 °C in a stream of dry air:
- 2 HIO3 → I2O5 + H2O
Heating metaperiodic acid to around 150 °C gives iodine pentoxide (I2O5) rather than the expected anhydride diiodine heptoxide (I2O7), while releasing oxygen as byproduct.[3]
- 2 HIO4 → I2O5 + H2O + O2
Projects
- Detection of carbon monoxide
- Make Al-I2O5 thermite
Handling
Safety
Iodine pentoxide is a powerful oxidizer and may ignite combustible materials on contact.
Storage
In closed airtight bottles.
Disposal
Should be reduced with sodium thiosulfate or some other reducing agent.
References
- Jump up ↑ IODINE Its Properties and Technical Applications, CHILEAN IODINE EDUCATIONAL BUREAU, INC., 120 Broadway, New York 5, New York, 1951
- Jump up ↑ https://www.youtube.com/watch?v=3ad5TjGGX94
- Jump up ↑ https://www.bionity.com/en/encyclopedia/Periodic_acid.html
