Iodine pentoxide

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Iodine pentoxide
Iodine-pentoxide-3D-balls.png
Iodine-pentoxide-3D-vdW.png
Identifiers
CAS number 12029-98-0 YesY
PubChem 159402
ChemSpider 140179 YesY
ChEBI CHEBI:29914 YesY
Jmol-3D images Image 1
Properties
Molecular formula I2O5
Molar mass 333.81 g/mol
Appearance white crystalline solid[1]
hygroscopic
Density 4.980 g/cm3[1]
Melting point 300 °C (572 °F; 573 K)[2] (decomposes)
Solubility soluble in nitric acid;
insoluble in ethanol, ether and CS2
Hazards
Main hazards oxidizer
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazard OX: Oxidizer. E.g., potassium perchlorateNFPA 704 four-colored diamond
Related compounds
Other anions iodine pentafluoride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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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 anhydride of iodine. It is produced by dehydrating iodic acid at 200 °C in a stream of dry air:[1]

2HIO3 → I2O5 + H2O

Structure[edit]

I2O5 is bent with an I-O-I angle of 139.2°, but the molecule has no mirror plane so its symmetry is not C2v. The terminal I-O distances are around 1.80 Å and the bridging I-O distances are around 1.95 Å.[3]

Reactions[edit]

Iodine pentoxide easily oxidises carbon monoxide to carbon dioxide at room temperature:

5CO + I2O5I2 + 5CO2

This reaction can be used to analyse the concentration of CO in a gaseous sample.

I2O5 forms iodyl salts, [IO2+], with SO3 and S2O6F2, but iodosyl salts, [IO+], with concentrated sulfuric acid.

Iodine pentoxide decomposes to iodine (vapor) and oxygen when heated to about 350 °C.[4]

See also[edit]

HI He
LiI BeI2 BI3 CI4 NI3 I2O4,
I2O5,
I4O9
IF,
IF3,
IF5,
IF7
Ne
NaI MgI2 AlI3 SiI4 PI3,
P2I4
S ICl,
ICl3
Ar
KI CaI2 Sc TiI4 VI3 CrI3 MnI2 FeI2 CoI2 NiI2 CuI ZnI2 Ga2I6 GeI2,
GeI4
AsI3 Se IBr Kr
RbI SrI2 Y ZrI4 Nb Mo Tc Ru Rh Pd AgI CdI2 InI3 SnI4,
SnI2
SbI3 TeI4 I Xe
CsI BaI2   Hf Ta W Re Os Ir Pt AuI Hg2I2,
HgI2
TlI PbI2 BiI3 Po AtI Rn
Fr Ra   Rf Db Sg Bh Hs Mt Ds Rg Cn Uut Fl Uup Lv Uus Uuo
La Ce Pr Nd Pm SmI2 Eu Gd TbI3 Dy Ho Er Tm Yb Lu
Ac ThI4 Pa UI3,
UI4
Np Pu Am Cm Bk Cf Es Fm Md No Lr

References[edit]

  1. ^ a b c Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 851–852. ISBN 0080379419. 
  2. ^ Patnaik, P. (2002). Handbook of Inorganic Chemicals. McGraw-Hill. ISBN 0-07-049439-8. 
  3. ^ Selte, K.; Kjekshus, A. (1970). "Iodine Oxides: Part III. The Crystal Structure of I2O5" (pdf). Acta Chemica Scandinavica 24 (6): 1912–1924. doi:10.3891/acta.chem.scand.24-1912. 
  4. ^ 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. (Google Books)