Iridium tetroxide (IrO
4, Iridium(VIII) oxide) is a binary
compound of
oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
and
iridium
Iridium is a chemical element; it has the symbol Ir and atomic number 77. This very hard, brittle, silvery-white transition metal of the platinum group, is considered the second-densest naturally occurring metal (after osmium) with a density ...
in
oxidation state
In chemistry, the oxidation state, or oxidation number, is the hypothetical Electrical charge, charge of an atom if all of its Chemical bond, bonds to other atoms are fully Ionic bond, ionic. It describes the degree of oxidation (loss of electrons ...
+8.
This compound was formed by photochemical rearrangement of (
η1-O2)IrO
2 in solid
argon
Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...
at a temperature of . At higher temperatures, the oxide is unstable.
The detection of the iridium tetroxide cation by
infrared photodissociation spectroscopy with formal oxidation state +9 has been reported, the highest currently known of any element.
However no
salts
In chemistry, a salt or ionic compound is a chemical compound consisting of an assembly of positively charged ions ( cations) and negatively charged ions (anions), which results in a compound with no net electric charge (electrically neutral). ...
are known, as attempted production of an Ir(IX) salt such as IrO
4 SbF6 did not result in anything.
References
External links
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{{Oxides
Tetroxide
Substances discovered in the 2000s
Transition metal oxides
Oxycations