Iridium(IV) oxide

Iridium(IV) oxide
Names
Other names
Iridium dioxide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.572 Edit this at Wikidata
UNII
  • InChI=1S/Ir.2O/q+4;2*-2 checkY
    Key: NSTASKGZCMXIET-UHFFFAOYSA-N checkY
  • InChI=1/Ir.2O/q+4;2*-2
    Key: NSTASKGZCMXIET-UHFFFAOYAQ
  • [Ir+4].[O-2].[O-2]
Properties
IrO2
Molar mass 224.22 g/mol
Appearance blue-black solid
Density 11.66 g/cm3
Melting point 1,100 °C (2,010 °F; 1,370 K) decomposes
insoluble
+224.0·10−6 cm3/mol
Structure
Rutile (tetragonal)
Octahedral (Ir); Trigonal (O)
Hazards
Flash point Non-flammable
Related compounds
Other anions
iridium(IV) fluoride, iridium disulfide
Other cations
rhodium dioxide, osmium dioxide, platinum dioxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Iridium(IV) oxide, IrO2, is the only well-characterised oxide of iridium. It is a blue-black solid. The compound adopts the TiO2 rutile structure, featuring six coordinate iridium and three coordinate oxygen.[1]

It is used with other rare oxides in the coating of anode-electrodes for industrial electrolysis and in microelectrodes for electrophysiology research.[2]

As described by its discoverers, it can be formed by treating the green form of iridium trichloride with oxygen at high temperatures:

2 IrCl3 + 2 O2 → 2 IrO2 + 3 Cl2

A hydrated form is also known.[3]

  1. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  2. ^ Cogan, Stuart F. (August 2008). "Neural Stimulation and Recording Electrodes". Annual Review of Biomedical Engineering. 10 (1): 275–309. doi:10.1146/annurev.bioeng.10.061807.160518. PMID 18429704.
  3. ^ H. L. Grube (1963). "The Platinum Metals". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. NY: Academic Press. p. 1590.